101
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Fadrique B, Baraloto C, Bravo‐Avila CH, Feeley KJ. Bamboo climatic tolerances are decoupled from leaf functional traits across an Andean elevation gradient. OIKOS 2022. [DOI: 10.1111/oik.09229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Belen Fadrique
- School of Geography, Univ. of Leeds Leeds UK
- International Center for Tropical Botany, Dept of Biological Sciences, Florida International Univ. Miami FL USA
| | | | - Catherine H. Bravo‐Avila
- International Center for Tropical Botany, Dept of Biological Sciences, Florida International Univ. Miami FL USA
| | - Kenneth J. Feeley
- Dept of Biology, Univ. of Miami Miami FL USA
- International Center for Tropical Botany, Dept of Biological Sciences, Florida International Univ. Miami FL USA
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102
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Teles CB, Magnago LFS, Carilo Filho LM, Piotto D. Relationship between the richness of tree species and edaphoclimatic characteristics of the south region of Bahia, Brazil. AUSTRAL ECOL 2022. [DOI: 10.1111/aec.13226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Carolina Barreto Teles
- Programa de Pós‐Graduação em Ecologia e Conservação da Biodiversidade, Departamento de Ciências Biológicas Universidade Estadual de Santa Cruz Rodovia Jorge Amado, Km 16, Bairro Salobrinho Ilhéus Bahia Brazil
| | - Luiz Fernando Silva Magnago
- Programa de Pós‐Graduação em Ecologia e Conservação da Biodiversidade, Departamento de Ciências Biológicas Universidade Estadual de Santa Cruz Rodovia Jorge Amado, Km 16, Bairro Salobrinho Ilhéus Bahia Brazil
- Universidade Federal do Sul da Bahia Itabuna Bahia Brazil
| | - Leildo Machado Carilo Filho
- Programa de Pós‐Graduação em Zoologia, Departamento de Ciências Biológicas Universidade Estadual de Santa Cruz Ilhéus Bahia Brazil
| | - Daniel Piotto
- Programa de Pós‐Graduação em Ecologia e Conservação da Biodiversidade, Departamento de Ciências Biológicas Universidade Estadual de Santa Cruz Rodovia Jorge Amado, Km 16, Bairro Salobrinho Ilhéus Bahia Brazil
- Universidade Federal do Sul da Bahia Itabuna Bahia Brazil
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103
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Duan H, Wang D, Zhao N, Huang G, Resco de Dios V, Tissue DT. Limited hydraulic recovery in seedlings of six tree species with contrasting leaf habits in subtropical China. FRONTIERS IN PLANT SCIENCE 2022; 13:967187. [PMID: 36035730 PMCID: PMC9403191 DOI: 10.3389/fpls.2022.967187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Subtropical tree species may experience severe drought stress due to variable rainfall under future climates. However, the capacity to restore hydraulic function post-drought might differ among co-occurring species with contrasting leaf habits (e.g., evergreen and deciduous) and have implications for future forest composition. Moreover, the links between hydraulic recovery and physiological and morphological traits related to water-carbon availability are still not well understood. Here, potted seedlings of six tree species (four evergreen and two deciduous) were grown outdoors under a rainout shelter. They grew under favorable water conditions until they were experimentally subjected to a soil water deficit leading to losses of ca. 50% of hydraulic conductivity, and then soils were re-watered to field capacity. Traits related to carbon and water relations were measured. There were differences in drought responses and recovery between species, but not as a function of evergreen or deciduous groups. Sapindus mukorossi exhibited the most rapid drought response, which was associated with a suite of physiological and morphological traits (larger plant size, the lowest hydraulic capacitance (C branch), higher minimum conductance (g min) and lower HV (Huber value)). Upon re-watering, xylem water potential exhibited fast recovery in 1-3 days among species, while photosynthesis at saturating light (A sat) and stomatal conductance (g s) recovery lagged behind water potential recovery depending on species, with g s recovery being more delayed than A sat in most species. Furthermore, none of the six species exhibited significant hydraulic recovery during the 7 days re-watering period, indicating that xylem refilling was apparently limited; in addition, NSC availability had a minimal role in facilitating hydraulic recovery during this short-term period. Collectively, if water supply is limited by insignificant hydraulic recovery post-drought, the observed carbon assimilation recovery of seedlings may not be sustained over the longer term, potentially altering seedling regeneration and shifting forest species composition in subtropical China under climate change.
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Affiliation(s)
- Honglang Duan
- Institute for Forest Resources and Environment of Guizhou, Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province, College of Forestry, Guizhou University, Guiyang, China
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems and Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang, China
| | - Defu Wang
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems and Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang, China
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Nan Zhao
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems and Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang, China
| | - Guomin Huang
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems and Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang, China
| | - Víctor Resco de Dios
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China
- Department of Crop and Forest Sciences, University of Lleida, Lleida, Spain
- Joint Research Unit CTFC-AGROTECNIO-CERCA Center, Lleida, Spain
| | - David T. Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
- Global Centre for Land-Based Innovation, Western Sydney University, Richmond, NSW, Australia
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104
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Petit G, Zambonini D, Hesse BD, Häberle K. No xylem phenotypic plasticity in mature Picea abies and Fagus sylvatica trees after 5 years of throughfall precipitation exclusion. GLOBAL CHANGE BIOLOGY 2022; 28:4668-4683. [PMID: 35555836 PMCID: PMC9325500 DOI: 10.1111/gcb.16232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
Forest trees are experiencing increasing frequency and intensity of drought events with climate change. We investigated xylem and phloem traits from mature Fagus sylvatica and Picea abies trees after 5 years of complete exclusion of throughfall precipitation during the growing season. Xylem and phloem anatomy, leaf and branch biomass were analysed along top branches of ~1.5 m lenght in 5 throughfall precipitation excluded (TE) and 5 control (CO) trees of both beech and spruce. Xylem traits were analysed on wood cores extracted from the stem at breast height. In the top branches of both species, the lumen diameter (or area) of xylem and phloem conduits did not differ between TE and CO trees. At breast height, TE trees of both species produced narrower xylem rings and conduits. While allocation to branch (BM) and needle biomass (LM) did not change between TE and CO in P. abies, TE F. sylvatica trees allocated proportionally more biomass to leaves (LM) than BM compared with CO. Despite artificial drought increased the mortality in the TE plots, our results revealed no changes in both xylem and phloem anatomies, undermining the hypothesis that successful acclimation to drought would primarily involve increased resistance against air embolism.
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Affiliation(s)
- Giai Petit
- Dipartimento Territorio e Sistemi Agro‐Forestali (TESAF)University of PadovaPadovaItaly
| | - Dario Zambonini
- Dipartimento Territorio e Sistemi Agro‐Forestali (TESAF)University of PadovaPadovaItaly
| | - Benjamin D. Hesse
- Land Surface‐Atmosphere InteractionsTechnical University of Munich, School of Life SciencesFreisingGermany
| | - Karl‐Heinz Häberle
- Chair of Restoration EcologyTechnical University of Munich, School of Life SciencesFreisingGermany
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105
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Eisenring M, Best RJ, Zierden MR, Cooper HF, Norstrem MA, Whitham TG, Grady K, Allan GJ, Lindroth RL. Genetic divergence along a climate gradient shapes chemical plasticity of a foundation tree species to both changing climate and herbivore damage. GLOBAL CHANGE BIOLOGY 2022; 28:4684-4700. [PMID: 35596651 DOI: 10.1111/gcb.16275] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/21/2022] [Indexed: 06/15/2023]
Abstract
Climate change is threatening the persistence of many tree species via independent and interactive effects on abiotic and biotic conditions. In addition, changes in temperature, precipitation, and insect attacks can alter the traits of these trees, disrupting communities and ecosystems. For foundation species such as Populus, phytochemical traits are key mechanisms linking trees with their environment and are likely jointly determined by interactive effects of genetic divergence and variable environments throughout their geographic range. Using reciprocal Fremont cottonwood (Populus fremontii) common gardens along a steep climatic gradient, we explored how environment (garden climate and simulated herbivore damage) and genetics (tree provenance and genotype) affect both foliar chemical traits and the plasticity of these traits. We found that (1) Constitutive and plastic chemical responses to changes in garden climate and damage varied among defense compounds, structural compounds, and leaf nitrogen. (2) For both defense and structural compounds, plastic responses to different garden climates depended on the climate in which a population or genotype originated. Specifically, trees originating from cool provenances showed higher defense plasticity in response to climate changes than trees from warmer provenances. (3) Trees from cool provenances growing in cool garden conditions expressed the lowest constitutive defense levels but the strongest induced (plastic) defenses in response to damage. (4) The combination of hot garden conditions and simulated herbivory switched the strategy used by these genotypes, increasing constitutive defenses but erasing the capacity for induction after damage. Because Fremont cottonwood chemistry plays a major role in shaping riparian communities and ecosystems, the effects of changes in phytochemical traits can be wide reaching. As the southwestern US is confronted with warming temperatures and insect outbreaks, these results improve our capacity to predict ecosystem consequences of climate change and inform selection of tree genotypes for conservation and restoration purposes.
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Affiliation(s)
- Michael Eisenring
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Forest Entomology, Swiss Federal Research Institute for Forest, Snow, and Landscape Research WSL, Zurich, Switzerland
| | - Rebecca J Best
- School of Earth and Sustainability, Northern Arizona University, Flagstaff, Arizona, USA
| | - Mark R Zierden
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Hillary F Cooper
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
| | - Madelyn A Norstrem
- School of Earth and Sustainability, Northern Arizona University, Flagstaff, Arizona, USA
| | - Thomas G Whitham
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Kevin Grady
- School of Forestry, Northern Arizona University, Flagstaff, Arizona, USA
| | - Gerard J Allan
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Richard L Lindroth
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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106
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Gomez‐Gallego M, Galiano L, Martínez‐Vilalta J, Stenlid J, Capador‐Barreto HD, Elfstrand M, Camarero JJ, Oliva J. Interaction of drought- and pathogen-induced mortality in Norway spruce and Scots pine. PLANT, CELL & ENVIRONMENT 2022; 45:2292-2305. [PMID: 35598958 PMCID: PMC9546048 DOI: 10.1111/pce.14360] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/11/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
Pathogenic diseases frequently occur in drought-stressed trees. However, their contribution to the process of drought-induced mortality is poorly understood. We combined drought and stem inoculation treatments to study the physiological processes leading to drought-induced mortality in Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) saplings infected with Heterobasidion annosum s.s. We analysed the saplings' water status, gas exchange, nonstructural carbohydrates (NSCs) and defence responses, and how they related to mortality. Saplings were followed for two growing seasons, including an artificially induced 3-month dormancy period. The combined drought and pathogen treatment significantly increased spruce mortality; however, no interaction between these stressors was observed in pine, although individually each stressor caused mortality. Our results suggest that pathogen infection decreased carbon reserves in spruce, reducing the capacity of saplings to cope with drought, resulting in increased mortality rates. Defoliation, relative water content and the starch concentration of needles were predictors of mortality in both species under drought and pathogen infection. Infection and drought stress create conflicting needs for carbon to compartmentalize the pathogen and to avoid turgor loss, respectively. Heterobasidion annosum reduces the functional sapwood area and shifts NSC allocation patterns, reducing the capacity of trees to cope with drought.
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Affiliation(s)
- Mireia Gomez‐Gallego
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
- Université de Lorraine, INRAE, IAMNancyFrance
| | - Lucia Galiano
- CREAF, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
| | - Jordi Martínez‐Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
| | - Jan Stenlid
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | - Hernán D. Capador‐Barreto
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | - Malin Elfstrand
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | | | - Jonàs Oliva
- Department of Crop and Forest SciencesUniversity of LleidaLleidaSpain
- Joint Research Unit CTFC‐AGROTECNIOLleidaSpain
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107
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Jiang (蒋国凤) GF, Li (李溯源) SY, Li (李艺蝉) YC, Roddy AB. Coordination of hydraulic thresholds across roots, stems, and leaves of two co-occurring mangrove species. PLANT PHYSIOLOGY 2022; 189:2159-2174. [PMID: 35640109 PMCID: PMC9342987 DOI: 10.1093/plphys/kiac240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/09/2022] [Indexed: 05/30/2023]
Abstract
Mangroves are frequently inundated with saline water and have evolved different anatomical and physiological mechanisms to filter and, in some species, excrete excess salt from the water they take up. Because salts impose osmotic stress, interspecific differences in salt tolerance and salt management strategy may influence physiological responses to drought throughout the entire plant hydraulic pathway, from roots to leaves. Here, we characterized embolism vulnerability simultaneously in leaves, stems, and roots of seedlings of two mangrove species (Avicennia marina and Bruguiera gymnorrhiza) along with turgor-loss points in roots and leaves and xylem anatomical traits. In both species, the water potentials causing 50% of total embolism were less negative in roots and leaves than they were in stems, but the water potentials causing incipient embolism (5%) were similar in roots, stems, and leaves. Stomatal closure in leaves and turgor loss in both leaves and roots occurred at water potentials only slightly less negative than the water potentials causing 5% of total embolism. Xylem anatomical traits were unrelated to vulnerability to embolism. Vulnerability segmentation may be important in limiting embolism spread into stems from more vulnerable roots and leaves. Interspecific differences in salt tolerance affected hydraulic traits from roots to leaves: the salt-secretor A. marina lost turgor at more negative water potentials and had more embolism-resistant xylem than the salt-excluder B. gymnorrhiza. Characterizing physiological thresholds of roots may help to explain recent mangrove mortality after drought and extended saltwater inundation.
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Affiliation(s)
| | - Su-Yuan Li (李溯源)
- Guangxi Key Laboratory of Forest Ecology and Conservation, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning 530004, China
| | - Yi-Chan Li (李艺蝉)
- Guangxi Key Laboratory of Forest Ecology and Conservation, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning 530004, China
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108
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Song Y, Sterck F, Zhou X, Liu Q, Kruijt B, Poorter L. Drought resilience of conifer species is driven by leaf lifespan but not by hydraulic traits. THE NEW PHYTOLOGIST 2022; 235:978-992. [PMID: 35474217 PMCID: PMC9322575 DOI: 10.1111/nph.18177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 04/14/2022] [Indexed: 06/14/2023]
Abstract
Increased droughts impair tree growth worldwide. This study analyzes hydraulic and carbon traits of conifer species, and how they shape species strategies in terms of their growth rate and drought resilience. We measured 43 functional stem and leaf traits for 28 conifer species growing in a 50-yr-old common garden experiment in the Netherlands. We assessed: how drought- and carbon-related traits are associated across species, how these traits affect stem growth and drought resilience, and how traits and drought resilience are related to species' climatic origin. We found two trait spectra: a hydraulics spectrum reflecting a trade-off between hydraulic and biomechanical safety vs hydraulic efficiency, and a leaf economics spectrum reflecting a trade-off between tough, long-lived tissues vs high carbon assimilation rate. Pit aperture size occupied a central position in the trait-based network analysis and also increased stem growth. Drought recovery decreased with leaf lifespan. Conifer species with long-lived leaves suffer from drought legacy effects, as drought-damaged leaves cannot easily be replaced, limiting growth recovery after drought. Leaf lifespan, rather than hydraulic traits, can explain growth responses to a drier future.
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Affiliation(s)
- Yanjun Song
- Forest Ecology and Forest Management GroupWageningen University and Research6700 AAWageningenthe Netherlands
| | - Frank Sterck
- Forest Ecology and Forest Management GroupWageningen University and Research6700 AAWageningenthe Netherlands
| | - Xiaqu Zhou
- Forest Ecology and Forest Management GroupWageningen University and Research6700 AAWageningenthe Netherlands
- Department of Earth and Environmental SciencesKU LeuvenPO Box 24113001LeuvenBelgium
| | - Qi Liu
- Forest Ecology and Forest Management GroupWageningen University and Research6700 AAWageningenthe Netherlands
| | - Bart Kruijt
- Water Systems and Global Change GroupWageningen University and Research6700 AAWageningenthe Netherlands
| | - Lourens Poorter
- Forest Ecology and Forest Management GroupWageningen University and Research6700 AAWageningenthe Netherlands
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109
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Zlobin IE. Linking the growth patterns of coniferous species with their performance under climate aridization. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154971. [PMID: 35367548 DOI: 10.1016/j.scitotenv.2022.154971] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/19/2022] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
Tree growth is highly sensitive to water deficit. At the same time, growth processes substantially influence tree performance under water stress by changing the root-absorbing surface, leaf-transpiring surface, amount of conducting xylem, etc. Drought-induced growth suppression is often higher in conifers than in broadleaf species. This review is devoted to the relations between the growth of coniferous plants and their performance under increasing climate aridization in the temperate and boreal zones of the Northern Hemisphere. For adult trees, available evidence suggests that increasing the frequency and severity of water deficit would be more detrimental to those plants that have higher growth in favorable conditions but decrease growth more prominently under water shortage, compared to trees whose growth is less sensitive to moisture availability. Not only the overall sensitivity of growth processes to water supply but also the asymmetry in response to lower-than-average and higher-than-average moisture conditions can be important for the performance of coniferous trees under upcoming adverse climate change. To fully understand the tree response under future climate change, the responses to both drier and wetter years need to be analyzed separately. In coniferous seedlings, more active growth is usually linked with better drought survival, although physiological reasons for such a link can be different. Growth stability under exacerbating summer water deficit in coniferous plants can be maintained by more active spring growth and/or by a bimodal growth pattern; each strategy has specific advantages and drawbacks. The optimal choice of growth strategy would be critical for future reforestation programs.
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Affiliation(s)
- Ilya E Zlobin
- K.A. Timiryazev Institute of Plant Physiology, RAS, 35 Botanicheskaya St., Moscow 127276, Russia.
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110
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Abstract
Forest ecosystems are strongly impacted by continuing climate change and increasing disturbance activity, but how forest dynamics will respond remains highly uncertain. Here, we argue that a short time window after disturbance (i.e., a discrete event that disrupts prevailing ecosystem structure and composition and releases resources) is pivotal for future forest development. Trees that establish during this reorganization phase can shape forest structure and composition for centuries, providing operational early indications of forest change. While forest change has been fruitfully studied through a lens of resilience, profound ecological changes can be masked by a resilience versus regime shift dichotomy. We present a framework for characterizing the full spectrum of change after disturbance, analyzing forest reorganization along dimensions of forest structure (number, size, and spatial arrangement of trees) and composition (identity and diversity of tree species). We propose four major pathways through which forest cover can persist but reorganize following disturbance: resilience (no change in structure and composition), restructuring (structure changes but composition does not), reassembly (composition changes but structure does not), and replacement (structure and composition both change). Regime shifts occur when vegetation structure and composition are altered so profoundly that the emerging trajectory leads to nonforest. We identify fundamental processes underpinning forest reorganization which, if disrupted, deflect ecosystems away from resilience. To understand and predict forest reorganization, assessing these processes and the traits modulating them is crucial. A new wave of experiments, measurements, and models emphasizing the reorganization phase will further the capacity to anticipate future forest dynamics.
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111
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Morcillo L, Muñoz-Rengifo JC, Torres-Ruiz JM, Delzon S, Moutahir H, Vilagrosa A. Post-drought conditions and hydraulic dysfunction determine tree resilience and mortality across Mediterranean Aleppo pine (Pinus halepensis) populations after an extreme drought event. TREE PHYSIOLOGY 2022; 42:1364-1376. [PMID: 35038335 DOI: 10.1093/treephys/tpac001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Drought-related tree mortality is a global phenomenon that currently affects a wide range of forests. Key functional variables on plant hydraulics, carbon economy, growth and allocation have been identified and play a role in tree drought responses. However, tree mortality thresholds based on such variables are difficult to identify, especially under field conditions. We studied several Aleppo pine populations differently affected by an extreme drought event in 2014, with mortality rates ranging from no mortality to 90% in the most severely affected population. We hypothesized that mortality is linked with high levels of xylem embolism, i.e., hydraulic dysfunction, which would also lead to lower tree resistance to drought in subsequent years. Despite not finding any differences among populations in the vulnerability curves to xylem embolism, there were large differences in the hydraulic safety margin (HSM) and the hydraulic dysfunction level. High mortality rates were associated with a negative HSM when xylem embolism reached values over 60%. We also found forest weakening and post-drought mortality related to a low hydraulic water transport capacity, reduced plant growth, low carbohydrate contents and high pest infestation rates. Our results highlight the importance of drought severity and the hydraulic dysfunction level on pine mortality, as well as post-drought conditions during recovery processes.
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Affiliation(s)
- L Morcillo
- Mediterranean Center for Environmental Studies (CEAM Foundation), Joint Research Unit University of Alicante-CEAM, University of Alicante, Alicante 03690, Spain
| | - J C Muñoz-Rengifo
- Department of Ecology, University of Alicante, Alicante 03690, Spain
- Department of Earth Science, Universidad Estatal Amazónica, Pastaza 160150, Ecuador
| | - J M Torres-Ruiz
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63000, France
| | - S Delzon
- Université Bordeaux, INRAE, BIOGECO, Pessac 33615, France
| | - H Moutahir
- Mediterranean Center for Environmental Studies (CEAM Foundation), Joint Research Unit University of Alicante-CEAM, University of Alicante, Alicante 03690, Spain
| | - A Vilagrosa
- Mediterranean Center for Environmental Studies (CEAM Foundation), Joint Research Unit University of Alicante-CEAM, University of Alicante, Alicante 03690, Spain
- Department of Ecology, University of Alicante, Alicante 03690, Spain
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112
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Detto M, Pacala SW. Plant hydraulics, stomatal control, and the response of a tropical forest to water stress over multiple temporal scales. GLOBAL CHANGE BIOLOGY 2022; 28:4359-4376. [PMID: 35373899 DOI: 10.1111/gcb.16179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
Many tropical regions are experiencing an intensification of drought, with increasing severity and frequency. The ecosystem response to these changes is still highly uncertain. On short time scales (from diurnal to seasonal), tropical forests respond to water stress by physiological controls, such as stomatal regulation and phenological adjustment, to cope with increasing atmospheric water demand and reduced water supply. However, the interactions among biological processes and co-varying environmental factors that determine the ecosystem-level fluxes are still unclear. Furthermore, climate variability at longer time scales, such as that generated by ENSO, produces less predictable effects because it depends on a highly stochastic combination of factors that might vary among forests and even between events in the same forest. This study will present some emerging patterns of response to water stress from 5 years of water, carbon, and energy fluxes observed on a seasonal tropical forest in central Panama, including an increase in productivity during the 2015 El Niño. These responses depend on the combination of environmental factors experienced by the forest throughout the seasonal cycle, in particular, increase in solar radiation, stimulating productivity, and increasing vapor pressure deficit (VPD) and decreasing soil moisture, limiting stomata opening. These results suggest a critical role of plant hydraulics in mediating the response to water stress over a broad range of temporal scales (diurnal, intraseasonal, seasonal, and interannual), by acclimating canopy conductance to light and VPD during different soil moisture regimes. A multilayer photosynthesis model coupled with a plant hydraulics scheme can reproduce these complex responses. However, results depend critically on parameters regulating water transport efficiency and the cost of water stress. As these costs have not been properly identified and quantified yet, more empirical research is needed to elucidate physiological mechanisms of hydraulic failure and recover, for example embolism repair and xylem regrowth.
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Affiliation(s)
- Matteo Detto
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
- Smithsonian Tropical Research Institute, Balboa, Panama
| | - Stephen W Pacala
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
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113
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Gea‐Izquierdo G, Sánchez‐González M. Forest disturbances and climate constrain carbon allocation dynamics in trees. GLOBAL CHANGE BIOLOGY 2022; 28:4342-4358. [PMID: 35322511 PMCID: PMC9541293 DOI: 10.1111/gcb.16172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/19/2022] [Indexed: 06/14/2023]
Abstract
Forest disturbances such as drought, fire, and logging affect the forest carbon dynamics and the terrestrial carbon sink. Forest mortality after disturbances creates uncertainties that need to be accounted for to understand forest dynamics and their associated C-sink. We combined data from permanent resampling plots and biomass oriented dendroecological plots to estimate time series of annual woody biomass growth (ABI) in several forests. ABI time series were used to benchmark a vegetation model to analyze dynamics in forest productivity and carbon allocation forced by environmental variability. The model implements source and sink limitations explicitly by dynamically constraining carbon allocation of assimilated photosynthates as a function of temperature and moisture. Bias in tree-ring reconstructed ABI increased back in time from data collection and with increasing disturbance intensity. ABI bias ranged from zero, in open stands without recorded mortality, to over 100% in stands with major disturbances such as thinning or snowstorms. Stand leaf area was still lower than in control plots decades after heavy thinning. Disturbances, species life-history strategy and climatic variability affected carbon-partitioning patterns in trees. Resprouting broadleaves reached maximum biomass growth at earlier ages than nonresprouting conifers. Environmental variability and leaf area explained much variability in woody biomass allocation. Effects of stand competition on C-allocation were mediated by changes in stand leaf area except after major disturbances. Divergence between tree-ring estimated and simulated ABI were caused by unaccounted changes in allocation or misrepresentation of some functional process independently of the model calibration approach. Higher disturbance intensity produced greater modifications of the C-allocation pattern, increasing error in reconstructed biomass dynamics. Legacy effects from disturbances decreased model performance and reduce the potential use of ABI as a proxy to net primary productivity. Trait-based dynamics of C-allocation in response to environmental variability need to be refined in vegetation models.
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114
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Climatic and biotic factors influencing regional declines and recovery of tropical forest biomass from the 2015/16 El Niño. Proc Natl Acad Sci U S A 2022; 119:e2101388119. [PMID: 35733266 PMCID: PMC9245643 DOI: 10.1073/pnas.2101388119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The 2015/16 El Niño brought severe drought and record-breaking temperatures in the tropics. Here, using satellite-based L-band microwave vegetation optical depth, we mapped changes of above-ground biomass (AGB) during the drought and in subsequent years up to 2019. Over more than 60% of drought-affected intact forests, AGB reduced during the drought, except in the wettest part of the central Amazon, where it declined 1 y later. By the end of 2019, only 40% of AGB reduced intact forests had fully recovered to the predrought level. Using random-forest models, we found that the magnitude of AGB losses during the drought was mainly associated with regionally distinct patterns of soil water deficits and soil clay content. For the AGB recovery, we found strong influences of AGB losses during the drought and of [Formula: see text]. [Formula: see text] is a parameter related to canopy structure and is defined as the ratio of two relative height (RH) metrics of Geoscience Laser Altimeter System (GLAS) waveform data-RH25 (25% energy return height) and RH100 (100% energy return height; i.e., top canopy height). A high [Formula: see text] may reflect forests with a tall understory, thick and closed canopy, and/or without degradation. Such forests with a high [Formula: see text] ([Formula: see text] ≥ 0.3) appear to have a stronger capacity to recover than low-[Formula: see text] ones. Our results highlight the importance of forest structure when predicting the consequences of future drought stress in the tropics.
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115
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Han H, Xi B, Wang Y, Feng J, Li X, Tissue DT. Lack of phenotypic plasticity in leaf hydraulics for 10 woody species common to urban forests of North China. TREE PHYSIOLOGY 2022; 42:1203-1215. [PMID: 35038332 DOI: 10.1093/treephys/tpac003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
The survival and performance of urban forests are increasingly challenged by urban drought, consequently compromising the sustainability and functionality of urban vegetation. Plant-water relations largely determine species drought tolerance, yet little is known about the hydraulics of urban forest species. Here, we report the leaf hydraulic and carbon traits that govern plant growth and drought resistance, including vulnerability to embolism, hydraulic conductivity and leaf gas exchange characteristics, as well as morphological traits that are potentially linked with these physiological attributes, with the aim of guiding species selection and management in urban forests. Plant materials were collected from mature shrubs and trees on our university campus in Beijing, representing 10 woody species common to urban forests in north China. We found that the leaf embolism resistance, represented by the water potential inducing 50% loss of hydraulic conductivity (P50), as well as the hydraulic safety margin (HSM) defined by P50 and the water potential threshold at the inception of embolism (P12), varied remarkably across species, but was unrelated to growth form. Likewise, stem and leaf-specific hydraulic conductivity (Kstem and kl) was also highly species-specific. Leaf P50 was positively correlated with hydraulic conductivity. However, neither P50 nor hydraulic conductivity was correlated with leaf gas exchange traits, including maximum photosynthetic rate (Amax) and stomatal conductance (gs). Plant morphological and physiological traits were not related, except for specific leaf area, which showed a negative relationship with HSM. Traits influencing plant-water transport were primarily correlated with the mean annual precipitation of species climatic niche. Overall, current common woody species in urban forest environments differed widely in their drought resistance and did not have the capacity to modify these characteristics in response to a changing climate. Species morphology provides limited information regarding physiological drought resistance. Thus, screening urban forest species based on plant physiology is essential to sustain the ecological services of urban forests.
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Affiliation(s)
- Hang Han
- College of Life and Environmental Science, Minzu University of China, 27 Zhongguancun South Avenue, Haidian District, Beijing 100081, People's Republic of China
| | - Benye Xi
- Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, People's Republic of China
| | - Ye Wang
- Beijing Academy of Forestry and Pomology Sciences, 12 A Rui Wang Fen, Fragrance Hills, Haidian District, Beijing 100093, People's Republic of China
| | - Jinchao Feng
- College of Life and Environmental Science, Minzu University of China, 27 Zhongguancun South Avenue, Haidian District, Beijing 100081, People's Republic of China
| | - Ximeng Li
- College of Life and Environmental Science, Minzu University of China, 27 Zhongguancun South Avenue, Haidian District, Beijing 100081, People's Republic of China
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
- Global Centre for Land-based Innovation, Western Sydney University, Hawkesbury Campus, Richmond, NSW 2753, Australia
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116
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Drought-exposure history increases complementarity between plant species in response to a subsequent drought. Nat Commun 2022; 13:3217. [PMID: 35680926 PMCID: PMC9184649 DOI: 10.1038/s41467-022-30954-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 05/18/2022] [Indexed: 01/10/2023] Open
Abstract
Growing threats from extreme climatic events and biodiversity loss have raised concerns about their interactive consequences for ecosystem functioning. Evidence suggests biodiversity can buffer ecosystem functioning during such climatic events. However, whether exposure to extreme climatic events will strengthen the biodiversity-dependent buffering effects for future generations remains elusive. We assess such transgenerational effects by exposing experimental grassland communities to eight recurrent summer droughts versus ambient conditions in the field. Seed offspring of 12 species are then subjected to a subsequent drought event in the glasshouse, grown individually, in monocultures or in 2-species mixtures. Comparing productivity between mixtures and monocultures, drought-selected plants show greater between-species complementarity than ambient-selected plants when recovering from the subsequent drought, causing stronger biodiversity effects on productivity and better recovery of drought-selected mixtures after the drought. These findings suggest exposure to recurrent climatic events can improve ecosystem responses to future events through transgenerational reinforcement of species complementarity. Using experimental communities of grassland species, this study shows that drought-exposure history can accelerate recovery from subsequent drought through increased niche complementarity between species. This transgenerational effect may enhance the sustainability of biodiversity and ecosystem functioning in a future with more frequent droughts.
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117
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Tropical tree mortality has increased with rising atmospheric water stress. Nature 2022; 608:528-533. [PMID: 35585230 DOI: 10.1038/s41586-022-04737-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 04/06/2022] [Indexed: 12/20/2022]
Abstract
Evidence exists that tree mortality is accelerating in some regions of the tropics1,2, with profound consequences for the future of the tropical carbon sink and the global anthropogenic carbon budget left to limit peak global warming below 2 °C. However, the mechanisms that may be driving such mortality changes and whether particular species are especially vulnerable remain unclear3-8. Here we analyse a 49-year record of tree dynamics from 24 old-growth forest plots encompassing a broad climatic gradient across the Australian moist tropics and find that annual tree mortality risk has, on average, doubled across all plots and species over the last 35 years, indicating a potential halving in life expectancy and carbon residence time. Associated losses in biomass were not offset by gains from growth and recruitment. Plots in less moist local climates presented higher average mortality risk, but local mean climate did not predict the pace of temporal increase in mortality risk. Species varied in the trajectories of their mortality risk, with the highest average risk found nearer to the upper end of the atmospheric vapour pressure deficit niches of species. A long-term increase in vapour pressure deficit was evident across the region, suggesting that thresholds involving atmospheric water stress, driven by global warming, may be a primary cause of increasing tree mortality in moist tropical forests.
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118
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Functional susceptibility of tropical forests to climate change. Nat Ecol Evol 2022; 6:878-889. [PMID: 35577983 DOI: 10.1038/s41559-022-01747-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 03/24/2022] [Indexed: 11/08/2022]
Abstract
Tropical forests are some of the most biodiverse ecosystems in the world, yet their functioning is threatened by anthropogenic disturbances and climate change. Global actions to conserve tropical forests could be enhanced by having local knowledge on the forests' functional diversity and functional redundancy as proxies for their capacity to respond to global environmental change. Here we create estimates of plant functional diversity and redundancy across the tropics by combining a dataset of 16 morphological, chemical and photosynthetic plant traits sampled from 2,461 individual trees from 74 sites distributed across four continents together with local climate data for the past half century. Our findings suggest a strong link between climate and functional diversity and redundancy with the three trait groups responding similarly across the tropics and climate gradient. We show that drier tropical forests are overall less functionally diverse than wetter forests and that functional redundancy declines with increasing soil water and vapour pressure deficits. Areas with high functional diversity and high functional redundancy tend to better maintain ecosystem functioning, such as aboveground biomass, after extreme weather events. Our predictions suggest that the lower functional diversity and lower functional redundancy of drier tropical forests, in comparison with wetter forests, may leave them more at risk of shifting towards alternative states in face of further declines in water availability across tropical regions.
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119
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Changes in Species and Functional Diversity of the Herb Layer of Riparian Forest despite Six Decades of Strict Protection. FORESTS 2022. [DOI: 10.3390/f13050747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The herb layer of temperate forests contributes to long-term forest ecosystem functioning and provisioning of ecosystem services. Therefore, a thorough understanding of its dynamics in the face of environmental changes is essential. This paper focuses on the species and functional diversity of the herb layer of riparian forests to verify how these two community components changed over time and under strict protection. The understory vegetation was surveyed on 42 semi-permanent plots in three time periods between 1960 and 2020. The overall pattern in vegetation changes that related to species richness and diversity, functional structure, and habitat conditions was analyzed using ordination and permutation techniques. We found significant changes in species composition and the functional structure of herbaceous vegetation over the last six decades. Forests were enriched with nutrient-demanding and alien species. A significant increase in functional diversity and the proportion of species with high SLA and canopy height was also observed, whereas changes in habitat conditions were insignificant. The observed trends indicate that the strict protection of forest communities within small and isolated reserves does not fully protect their species composition. Forest reserves should be surrounded by unmanaged forests and spatially connected to allow species mobility.
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120
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Anderegg WRL, Chegwidden OS, Badgley G, Trugman AT, Cullenward D, Abatzoglou JT, Hicke JA, Freeman J, Hamman JJ. Future climate risks from stress, insects and fire across US forests. Ecol Lett 2022; 25:1510-1520. [PMID: 35546256 PMCID: PMC9321543 DOI: 10.1111/ele.14018] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/28/2022] [Accepted: 04/09/2022] [Indexed: 12/04/2022]
Abstract
Forests are currently a substantial carbon sink globally. Many climate change mitigation strategies leverage forest preservation and expansion, but rely on forests storing carbon for decades to centuries. Yet climate‐driven disturbances pose critical risks to the long‐term stability of forest carbon. We quantify the climate drivers that influence wildfire and climate stress‐driven tree mortality, including a separate insect‐driven tree mortality, for the contiguous United States for current (1984–2018) and project these future disturbance risks over the 21st century. We find that current risks are widespread and projected to increase across different emissions scenarios by a factor of >4 for fire and >1.3 for climate‐stress mortality. These forest disturbance risks highlight pervasive climate‐sensitive disturbance impacts on US forests and raise questions about the risk management approach taken by forest carbon offset policies. Our results provide US‐wide risk maps of key climate‐sensitive disturbances for improving carbon cycle modeling, conservation and climate policy.
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Affiliation(s)
| | | | - Grayson Badgley
- Blackrock Forest, Cornwall, New York, USA.,Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA
| | - Anna T Trugman
- Department of Geography, University of California, Santa Barbara, Santa Barbara, California, USA
| | - Danny Cullenward
- CarbonPlan, San Francisco, California, USA.,Institute for Carbon Removal Law and Policy, American University, Washington, DC, USA
| | - John T Abatzoglou
- Management of Complex Systems Department, University of California, Merced, Merced, California, USA
| | - Jeffrey A Hicke
- Department of Geography, University of Idaho, Moscow, Idaho, USA
| | | | - Joseph J Hamman
- CarbonPlan, San Francisco, California, USA.,National Center for Atmospheric Research, Boulder, Colorado, USA
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121
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Momayyezi M, Borsuk AM, Brodersen CR, Gilbert ME, Théroux‐Rancourt G, Kluepfel DA, McElrone AJ. Desiccation of the leaf mesophyll and its implications for CO 2 diffusion and light processing. PLANT, CELL & ENVIRONMENT 2022; 45:1362-1381. [PMID: 35141930 PMCID: PMC9314819 DOI: 10.1111/pce.14287] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 01/18/2022] [Accepted: 01/24/2022] [Indexed: 05/09/2023]
Abstract
Leaves balance CO2 and radiative absorption while maintaining water transport to maximise photosynthesis. Related species with contrasting leaf anatomy can provide insights into inherent and stress-induced links between structure and function for commonly measured leaf traits for important crops. We used two walnut species with contrasting mesophyll anatomy to evaluate these integrated exchange processes under non-stressed and drought conditions using a combination of light microscopy, X-ray microCT, gas exchange, hydraulic conductance, and chlorophyll distribution profiles through leaves. Juglans regia had thicker palisade mesophyll, higher fluorescence in the palisade, and greater low-mesophyll porosity that were associated with greater gas-phase diffusion (gIAS ), stomatal and mesophyll (gm ) conductances and carboxylation capacity. More and highly-packed mesophyll cells and bundle sheath extensions (BSEs) in Juglans microcarpa led to higher fluorescence in the spongy and in proximity to the BSEs. Both species exhibited drought-induced reductions in mesophyll cell volume, yet the associated increases in porosity and gIAS were obscured by declines in biochemical activity that decreased gm . Inherent differences in leaf anatomy between the species were linked to differences in gas exchange, light absorption and photosynthetic capacity, and drought-induced changes in leaf structure impacted performance via imposing species-specific limitations to light absorption, gas exchange and hydraulics.
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Affiliation(s)
- Mina Momayyezi
- Department of Viticulture and EnologyUniversity of CaliforniaDavisCaliforniaUSA
| | - Aleca M. Borsuk
- School of the EnvironmentYale UniversityNew HavenConnecticutUSA
| | | | | | | | | | - Andrew J. McElrone
- Department of Viticulture and EnologyUniversity of CaliforniaDavisCaliforniaUSA
- USDA‐ARSCrops Pathology and Genetics Research UnitDavisCaliforniaUSA
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122
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Hajek P, Link RM, Nock CA, Bauhus J, Gebauer T, Gessler A, Kovach K, Messier C, Paquette A, Saurer M, Scherer-Lorenzen M, Rose L, Schuldt B. Mutually inclusive mechanisms of drought-induced tree mortality. GLOBAL CHANGE BIOLOGY 2022; 28:3365-3378. [PMID: 35246895 DOI: 10.1101/2020.12.17.423038] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/16/2021] [Indexed: 05/22/2023]
Abstract
Unprecedented tree dieback across Central Europe caused by recent global change-type drought events highlights the need for a better mechanistic understanding of drought-induced tree mortality. Although numerous physiological risk factors have been identified, the importance of two principal mechanisms, hydraulic failure and carbon starvation, is still debated. It further remains largely unresolved how the local neighborhood composition affects individual mortality risk. We studied 9435 young trees of 12 temperate species planted in a diversity experiment in 2013 to assess how hydraulic traits, carbon dynamics, pest infestation, tree height and neighborhood competition influence individual mortality risk. Following the most extreme global change-type drought since record in 2018, one third of these trees died. Across species, hydraulic safety margins (HSMs) were negatively and a shift towards a higher sugar fraction in the non-structural carbohydrate (NSC) pool positively associated with mortality risk. Moreover, trees infested by bark beetles had a higher mortality risk, and taller trees a lower mortality risk. Most neighborhood interactions were beneficial, although neighborhood effects were highly species-specific. Species that suffered more from drought, especially Larix spp. and Betula spp., tended to increase the survival probability of their neighbors and vice versa. While severe tissue dehydration marks the final stage of drought-induced tree mortality, we show that hydraulic failure is interrelated with a series of other, mutually inclusive processes. These include shifts in NSC pools driven by osmotic adjustment and/or starch depletion as well as pest infestation and are modulated by the size and species identity of a tree and its neighbors. A more holistic view that accounts for multiple causes of drought-induced tree mortality is required to improve predictions of trends in global forest dynamics and to identify mutually beneficial species combinations.
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Affiliation(s)
- Peter Hajek
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Roman M Link
- Chair of Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Institute of Biological Sciences, Würzburg, Germany
| | - Charles A Nock
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Jürgen Bauhus
- Chair of Silviculture, University of Freiburg, Freiburg, Germany
| | - Tobias Gebauer
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- ETH Zurich, Institute of Terrestrial Ecosystems, Zurich, Switzerland
| | - Kyle Kovach
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Christian Messier
- Center for Forest Research, Université du Québec à Montréal, Montréal, Quebec, Canada
- University of Quebec in Outaouais (UQO), Institut des Sciences de la Forêt Tempérée (ISFORT), Gatineau, Quebec, Canada
| | - Alain Paquette
- Center for Forest Research, Université du Québec à Montréal, Montréal, Quebec, Canada
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
| | | | - Laura Rose
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Bernhard Schuldt
- Chair of Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Institute of Biological Sciences, Würzburg, Germany
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123
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Flexas J, Zhang Y, Gulías J, Xiong D, Carriquí M, Baraza E, Du T, Lei Z, Meng H, Dou H, Ribas-Carbo M, Xiang D, Xu W. Leaf physiological traits of plants from the Qinghai-Tibet Plateau and other arid sites in China: Identifying susceptible species and well-adapted extremophiles. JOURNAL OF PLANT PHYSIOLOGY 2022; 272:153689. [PMID: 35398716 DOI: 10.1016/j.jplph.2022.153689] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 06/14/2023]
Abstract
Extreme environments, such as deserts and high-elevation ecosystems, are very important from biodiversity and ecological perspectives. However, plant physiology at those sites has been scarcely studied, likely due to logistic difficulties. In the present study, leaf physiological traits in native plants were analyzed from arid zones across an elevational transect in Western China, from Turpan Basin to the Qinghai-Tibet Plateau (QTP) at Delingha. The aim of this study was to use leaf physiological traits to help identifying potentially threatened species and true extremophiles. Physiological measurements in the field, and particularly in situ measurements of gas exchange and chlorophyll fluorescence, have been determined to be useful to determine the current state of plants at a given environment. Using this approach plus a combination of leaf traits, several species performing particularly well at the QTP were identified, e.g. Hedysarum multijugum, as well as at Manas drylands, e.g. Peganum harmala and Setaria viridis. On the other hand, several species showed marked signs of severe stress, in particular a very low photosynthetic rate over its potential maximum, as well as other negative traits, like low water and/or nitrogen-use-efficiency, which should be considered in conservation plans. Interestingly, all C4 species studied except Setaria viridis were among the most stressed species. Despite their higher water use efficiency and drought-tolerance reputation, they presented a much larger photosynthesis depression than most C3 species. This is an intriguing and interesting observation that deserves further studies.
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Affiliation(s)
- Jaume Flexas
- Research Group on Plant Biology Under Mediterranean Conditions, Department de Biologia, Universitat de Les Illes Balears (UIB) - Agro-Environmental and Water Economics Institute (INAGEA), Carretera de Valldemossa Km 7.5, 07122, Palma, Illes Balears, Spain; King Abdulaziz University, P.O. Box 80200, Jeddah, 21589, Saudi Arabia.
| | - Yali Zhang
- Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Corps / College of Agriculture/College of Life Science, Shihezi University, Shihezi, Xinjiang, 832003, China.
| | - Javier Gulías
- Research Group on Plant Biology Under Mediterranean Conditions, Department de Biologia, Universitat de Les Illes Balears (UIB) - Agro-Environmental and Water Economics Institute (INAGEA), Carretera de Valldemossa Km 7.5, 07122, Palma, Illes Balears, Spain
| | - Dongliang Xiong
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Marc Carriquí
- Research Group on Plant Biology Under Mediterranean Conditions, Department de Biologia, Universitat de Les Illes Balears (UIB) - Agro-Environmental and Water Economics Institute (INAGEA), Carretera de Valldemossa Km 7.5, 07122, Palma, Illes Balears, Spain
| | - Elena Baraza
- Research Group on Plant Biology Under Mediterranean Conditions, Department de Biologia, Universitat de Les Illes Balears (UIB) - Agro-Environmental and Water Economics Institute (INAGEA), Carretera de Valldemossa Km 7.5, 07122, Palma, Illes Balears, Spain
| | - Tingting Du
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhangying Lei
- Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Corps / College of Agriculture/College of Life Science, Shihezi University, Shihezi, Xinjiang, 832003, China
| | - Haofeng Meng
- Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Corps / College of Agriculture/College of Life Science, Shihezi University, Shihezi, Xinjiang, 832003, China
| | - Haitao Dou
- Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Corps / College of Agriculture/College of Life Science, Shihezi University, Shihezi, Xinjiang, 832003, China
| | - Miquel Ribas-Carbo
- Research Group on Plant Biology Under Mediterranean Conditions, Department de Biologia, Universitat de Les Illes Balears (UIB) - Agro-Environmental and Water Economics Institute (INAGEA), Carretera de Valldemossa Km 7.5, 07122, Palma, Illes Balears, Spain
| | - Dao Xiang
- Wulanwusu Agro-Meteorological Experiment Station of Xinjiang / Wulanwusu National Comprehensive Meteorological Observation Special Test Field, Wulanwusu, 832199, Xinjiang, China
| | - Wenbin Xu
- Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Corps / College of Agriculture/College of Life Science, Shihezi University, Shihezi, Xinjiang, 832003, China
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Shen JX, Zhang YJ, Maenpuen P, Zhang SB, Zhang L, Yang L, Tao LB, Yan PY, Zhang ZM, Li SQ, Yuan X, Kongjarat W, Kaewkamol S, Tinprabat P, Chen YJ. Response of four evergreen savanna shrubs to an incidence of extreme drought: high embolism resistance, branch shedding and maintenance of nonstructural carbohydrates. TREE PHYSIOLOGY 2022; 42:740-753. [PMID: 35020937 DOI: 10.1093/treephys/tpab150] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/20/2021] [Indexed: 06/14/2023]
Abstract
Extreme drought events are becoming frequent globally, resulting in widespread plant mortality and forest dieback. Although savanna vegetation cover ~20% of the earth's land area, their responses to extreme drought have been less studied than that of forests. Herein, we quantified branch dieback, individual mortality and the associated physiological responses of four evergreen shrubs (Tarenna depauperate Hutch., Maytenus esquirolii (H. Lév.) C.Y. Cheng, Murraya exotica L., Jasminum nudiflorum Lindl.) in a savanna ecosystem in Southwest China to an incidence of extreme drought during 2019 and 2020. We found that 80-100% of the individuals of these species exhibited branch dieback, whereas individual mortality was only found in T. depauperate (4.5%). All species showed high resistance to stem embolism (P50, water potential at 50% loss of hydraulic conductivity ranged from -5.62 to -8.6 MPa), whereas the stem minimum water potentials reached -7.6 to ca -10.0 MPa during the drought. The low water potential caused high native embolism levels (percentage loss of hydraulic conductivity (PLC) 23-65%) in terminal branches, and the remaining stems maintained 15-35% PLC at the end of the drought. Large within-individual variations in stem vulnerability to embolism were detected, and shedding of vulnerable branches could be a mechanism for shrubs to reduce water and carbon consumption. Overall, the content of total nonstructural carbohydrates (NSC) and their components in the stem were generally comparable to or higher than those in the rainy season in three of the four species. Because the leaves were turgor-less for most time during the drought, high NSC levels during the drought could be due to recycling of NSC from dead branches or translocation from roots. Our results suggest high tolerance of savanna shrub species to extreme drought, which could be facilitated by high embolism resistance in some stems and shedding of vulnerable branches to maintain individual water and carbon balance.
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Affiliation(s)
- Jing-Xian Shen
- Institute of Ecology and Geobotany, School of Ecology and Environmental Sciences, Yunnan University, Kunming, Yunnan 650091, China
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- Yuanjiang Savanna Ecosystem Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yuanjiang, Yunnan 6663300, China
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, ME 04469, USA
| | - Phisamai Maenpuen
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Shu-Bin Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, China
| | - Lan Zhang
- School of Geography and Ecotoursim, Southwest Forestry University, Panlong District, Kunming, Yunnan 650224, China
| | - Lin Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
| | - Lian-Bin Tao
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
| | - Peng-Yun Yan
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
| | - Zhi-Ming Zhang
- Institute of Ecology and Geobotany, School of Ecology and Environmental Sciences, Yunnan University, Kunming, Yunnan 650091, China
| | - Shu-Qiong Li
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Xia Yuan
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Wanwalee Kongjarat
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Sasiwimol Kaewkamol
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Pimnara Tinprabat
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Ya-Jun Chen
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- Yuanjiang Savanna Ecosystem Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yuanjiang, Yunnan 6663300, China
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, China
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Yunnan 666303, China
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125
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Klein T, Torres-Ruiz JM, Albers JJ. Conifer desiccation in the 2021 NW heatwave confirms the role of hydraulic damage. TREE PHYSIOLOGY 2022; 42:722-726. [PMID: 35084498 DOI: 10.1093/treephys/tpac007] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
The unprecedented heatwave which hit the Pacific northwest of North America in late June-early July 2021 impacted ecosystems and communities, yet evidence for and analysis of this impact are still missing. Here we bring a unique dataset quantifying the impact on conifer trees, which are keystone species of many northwest ecosystems. Moreover, we take advantage of this exceptional event as a broad, extreme, 'field experiment' to test a fundamental theory in plant physiology and prepare our forests for a harsher future. Overall, the data collected confirm the role of hydraulic vulnerability in drought-induced injury to trees.
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Affiliation(s)
- Tamir Klein
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Jose M Torres-Ruiz
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63000, France
| | - John J Albers
- Albers Marcovina Vista Gardens, Bremerton, WA 98310-2150, USA
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
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126
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Hammond WM, Williams AP, Abatzoglou JT, Adams HD, Klein T, López R, Sáenz-Romero C, Hartmann H, Breshears DD, Allen CD. Global field observations of tree die-off reveal hotter-drought fingerprint for Earth's forests. Nat Commun 2022; 13:1761. [PMID: 35383157 PMCID: PMC8983702 DOI: 10.1038/s41467-022-29289-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 03/01/2022] [Indexed: 11/09/2022] Open
Abstract
Earth's forests face grave challenges in the Anthropocene, including hotter droughts increasingly associated with widespread forest die-off events. But despite the vital importance of forests to global ecosystem services, their fates in a warming world remain highly uncertain. Lacking is quantitative determination of commonality in climate anomalies associated with pulses of tree mortality-from published, field-documented mortality events-required for understanding the role of extreme climate events in overall global tree die-off patterns. Here we established a geo-referenced global database documenting climate-induced mortality events spanning all tree-supporting biomes and continents, from 154 peer-reviewed studies since 1970. Our analysis quantifies a global "hotter-drought fingerprint" from these tree-mortality sites-effectively a hotter and drier climate signal for tree mortality-across 675 locations encompassing 1,303 plots. Frequency of these observed mortality-year climate conditions strongly increases nonlinearly under projected warming. Our database also provides initial footing for further community-developed, quantitative, ground-based monitoring of global tree mortality.
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Affiliation(s)
- William M. Hammond
- grid.15276.370000 0004 1936 8091Agronomy Department, University of Florida, Gainesville, FL 32611 USA
| | - A. Park Williams
- grid.19006.3e0000 0000 9632 6718Department of Geography, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - John T. Abatzoglou
- grid.266096.d0000 0001 0049 1282Management of Complex Systems, University of California, Merced, CA USA
| | - Henry D. Adams
- grid.30064.310000 0001 2157 6568School of the Environment, Washington State University, Pullman, WA USA
| | - Tamir Klein
- grid.13992.300000 0004 0604 7563Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Rosana López
- grid.5690.a0000 0001 2151 2978Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain
| | - Cuauhtémoc Sáenz-Romero
- grid.412205.00000 0000 8796 243XInstituto de Investigaciones sobre los Recursos Naturales, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán Mexico
| | - Henrik Hartmann
- grid.419500.90000 0004 0491 7318Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - David D. Breshears
- grid.134563.60000 0001 2168 186XSchool of Natural Resources and the Environment, University of Arizona, Tucson, AZ USA
| | - Craig D. Allen
- grid.266832.b0000 0001 2188 8502Department of Geography and Environmental Studies, University of New Mexico, Albuquerque, NM USA
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127
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Li X, Xi B, Wu X, Choat B, Feng J, Jiang M, Tissue D. Unlocking Drought-Induced Tree Mortality: Physiological Mechanisms to Modeling. FRONTIERS IN PLANT SCIENCE 2022; 13:835921. [PMID: 35444681 PMCID: PMC9015645 DOI: 10.3389/fpls.2022.835921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Drought-related tree mortality has become a major concern worldwide due to its pronounced negative impacts on the functioning and sustainability of forest ecosystems. However, our ability to identify the species that are most vulnerable to drought, and to pinpoint the spatial and temporal patterns of mortality events, is still limited. Model is useful tools to capture the dynamics of vegetation at spatiotemporal scales, yet contemporary land surface models (LSMs) are often incapable of predicting the response of vegetation to environmental perturbations with sufficient accuracy, especially under stressful conditions such as drought. Significant progress has been made regarding the physiological mechanisms underpinning plant drought response in the past decade, and plant hydraulic dysfunction has emerged as a key determinant for tree death due to water shortage. The identification of pivotal physiological events and relevant plant traits may facilitate forecasting tree mortality through a mechanistic approach, with improved precision. In this review, we (1) summarize current understanding of physiological mechanisms leading to tree death, (2) describe the functionality of key hydraulic traits that are involved in the process of hydraulic dysfunction, and (3) outline their roles in improving the representation of hydraulic function in LSMs. We urge potential future research on detailed hydraulic processes under drought, pinpointing corresponding functional traits, as well as understanding traits variation across and within species, for a better representation of drought-induced tree mortality in models.
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Affiliation(s)
- Ximeng Li
- College of Life and Environmental Science, Minzu University of China, Beijing, China
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Benye Xi
- Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing, China
| | - Xiuchen Wu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Jinchao Feng
- College of Life and Environmental Science, Minzu University of China, Beijing, China
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - David Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Global Centre for Land-based Innovation, Western Sydney University, Richmond, NSW, Australia
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128
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Mantova M, Herbette S, Cochard H, Torres-Ruiz JM. Hydraulic failure and tree mortality: from correlation to causation. TRENDS IN PLANT SCIENCE 2022; 27:335-345. [PMID: 34772610 DOI: 10.1016/j.tplants.2021.10.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 09/27/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
Xylem hydraulic failure has been recognized as a pervasive factor in the triggering of drought-induced tree mortality. However, foundational evidence of the mechanistic link connecting hydraulic failure with living cell damage and tree death has not been identified yet, compromising our ability to predict mortality events. Meristematic cells are involved in the recovery of trees from drought, and focusing on their vitality and functionality after a drought event could provide novel information on the mechanistic link between hydraulic failure and drought-induced tree mortality. In this Opinion, we focus on the cell's critical hydration status for tree recovery from drought and how it links with the membrane integrity of the meristems.
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Affiliation(s)
- Marylou Mantova
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Stéphane Herbette
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Hervé Cochard
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - José M Torres-Ruiz
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France.
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129
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Avila RT, Guan X, Kane CN, Cardoso AA, Batz TA, DaMatta FM, Jansen S, McAdam SAM. Xylem embolism spread is largely prevented by interconduit pit membranes until the majority of conduits are gas-filled. PLANT, CELL & ENVIRONMENT 2022; 45:1204-1215. [PMID: 34984700 DOI: 10.1111/pce.14253] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 11/29/2021] [Accepted: 12/11/2021] [Indexed: 06/14/2023]
Abstract
Xylem embolism resistance varies across species influencing drought tolerance, yet little is known about the determinants of the embolism resistance of an individual conduit. Here we conducted an experiment using the optical vulnerability method to test whether individual conduits have a specific water potential threshold for embolism formation and whether pre-existing embolism in neighbouring conduits alters this threshold. Observations were made on a diverse sample of angiosperm and conifer species through a cycle of dehydration, rehydration and subsequent dehydration to death. Upon rehydration after the formation of embolism, no refilling was observed. When little pre-existing embolism was present, xylem conduits had a conserved, individual embolism-resistance threshold that varied across the population of conduits. The consequence of a variable conduit-specific embolism threshold is that a small degree of pre-existing embolism in the xylem results in apparently more resistant xylem in subsequent dehydrations, particularly in angiosperms with vessels. While our results suggest that pit membranes separating xylem conduits are critical for maintaining a conserved individual conduit threshold for embolism when little pre-existing embolism is present, as the percentage of embolized conduits increases, gas movement, local pressure differences and connectivity between conduits increasingly contribute to embolism spread.
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Affiliation(s)
- Rodrigo T Avila
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
| | - Xinyi Guan
- Institute of Systematic Botany and Ecology, Faculty of Natural Sciences, Ulm University, Ulm, Baden-Württemberg, Germany
| | - Cade N Kane
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
| | - Amanda A Cardoso
- Instituto de Ciências da Natureza, Universidade Federal de Alfenas, Alfenas, Brazil
| | - Timothy A Batz
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
| | - Fábio M DaMatta
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Faculty of Natural Sciences, Ulm University, Ulm, Baden-Württemberg, Germany
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
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130
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Guillemot J, Martin-StPaul NK, Bulascoschi L, Poorter L, Morin X, Pinho BX, le Maire G, R L Bittencourt P, Oliveira RS, Bongers F, Brouwer R, Pereira L, Gonzalez Melo GA, Boonman CCF, Brown KA, Cerabolini BEL, Niinemets Ü, Onoda Y, Schneider JV, Sheremetiev S, Brancalion PHS. Small and slow is safe: On the drought tolerance of tropical tree species. GLOBAL CHANGE BIOLOGY 2022; 28:2622-2638. [PMID: 35007364 DOI: 10.1111/gcb.16082] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 12/09/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Understanding how evolutionary history and the coordination between trait trade-off axes shape the drought tolerance of trees is crucial to predict forest dynamics under climate change. Here, we compiled traits related to drought tolerance and the fast-slow and stature-recruitment trade-off axes in 601 tropical woody species to explore their covariations and phylogenetic signals. We found that xylem resistance to embolism (P50) determines the risk of hydraulic failure, while the functional significance of leaf turgor loss point (TLP) relies on its coordination with water use strategies. P50 and TLP exhibit weak phylogenetic signals and substantial variation within genera. TLP is closely associated with the fast-slow trait axis: slow species maintain leaf functioning under higher water stress. P50 is associated with both the fast-slow and stature-recruitment trait axes: slow and small species exhibit more resistant xylem. Lower leaf phosphorus concentration is associated with more resistant xylem, which suggests a (nutrient and drought) stress-tolerance syndrome in the tropics. Overall, our results imply that (1) drought tolerance is under strong selective pressure in tropical forests, and TLP and P50 result from the repeated evolutionary adaptation of closely related taxa, and (2) drought tolerance is coordinated with the ecological strategies governing tropical forest demography. These findings provide a physiological basis to interpret the drought-induced shift toward slow-growing, smaller, denser-wooded trees observed in the tropics, with implications for forest restoration programmes.
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Affiliation(s)
- Joannès Guillemot
- CIRAD, UMR Eco&Sols, Piracicaba, São Paulo, Brazil
- Eco&Sols, Univ. Montpellier, CIRAD, INRAe, Institut Agro, IRD, Montpellier, France
- Department of Forest Sciences, ESALQ, University of São Paulo, Piracicaba, São Paulo, Brazil
| | | | - Leticia Bulascoschi
- Department of Forest Sciences, ESALQ, University of São Paulo, Piracicaba, São Paulo, Brazil
| | - Lourens Poorter
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
| | - Xavier Morin
- CEFE, CNRS, Univ. Montpellier, EPHE, IRD, Univ. Paul Valéry Montpellier 3, Montpellier, France
| | - Bruno X Pinho
- AMAP, Univ Montpellier, INRAe, CIRAD, CNRS, IRD, Montpellier, France
- Departamento de Botânica, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Guerric le Maire
- CIRAD, UMR Eco&Sols, Piracicaba, São Paulo, Brazil
- Eco&Sols, Univ. Montpellier, CIRAD, INRAe, Institut Agro, IRD, Montpellier, France
| | | | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil
| | - Frans Bongers
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
| | - Rens Brouwer
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
| | - Luciano Pereira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | | | - Coline C F Boonman
- Department of Aquatic Ecology and Environmental Biology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | - Kerry A Brown
- Department of Geography, Geology and the Environment, Kingston University London, Kingston Upon Thames, UK
| | - Bruno E L Cerabolini
- Department of Biotechnologies and Life Sciences (DBSV), University of Insubria, Varese, Italy
| | - Ülo Niinemets
- Estonian University of Life Sciences, Tartu, Estonia
| | - Yusuke Onoda
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Julio V Schneider
- Department of Botany and Molecular Evolution, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt, Germany
- Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt, Germany
| | | | - Pedro H S Brancalion
- Department of Forest Sciences, ESALQ, University of São Paulo, Piracicaba, São Paulo, Brazil
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131
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Duan H, Resco de Dios V, Wang D, Zhao N, Huang G, Liu W, Wu J, Zhou S, Choat B, Tissue DT. Testing the limits of plant drought stress and subsequent recovery in four provenances of a widely distributed subtropical tree species. PLANT, CELL & ENVIRONMENT 2022; 45:1187-1203. [PMID: 34985807 DOI: 10.1111/pce.14254] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 12/05/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
Drought-induced tree mortality may increase with ongoing climate change. Unraveling the links between stem hydraulics and mortality thresholds, and the effects of intraspecific variation, remain important unresolved issues. We conducted a water manipulation experiment in a rain-out shelter, using four provenances of Schima superba originating from a gradient of annual precipitation (1124-1796 mm) and temperature (16.4-22.4°C). Seedlings were droughted to three levels of percentage loss of hydraulic conductivity (i.e., P50 , P88 and P99) and subsequently rewatered to field capacity for 30 days; traits related to water and carbon relations were measured. The lethal water potential associated with incipient mortality was between P50 and P88 . Seedlings exhibited similar drought responses in xylem water potential, hydraulic conductivity and gas exchange. Upon rehydration, patterns of gas exchange differed among provenances but were not related to the climate at the origin. The four provenances exhibited a similar degree of stem hydraulic recovery, which was correlated with the magnitude of antecedent drought and stem soluble sugar at the end of the drought. Results suggest that there were intraspecific differences in the capacity of S. superba seedlings for carbon assimilation during recovery, indicating a decoupling between gas exchange recovery and stem hydraulics across provenances.
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Affiliation(s)
- Honglang Duan
- Institute for Forest Resources and Environment of Guizhou, Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province, College of Forestry, Guizhou University, Guiyang, China
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems & Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang, China
| | - Víctor Resco de Dios
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China
- Department of Crop and Forest Sciences, Unversitat de Lleida, Lleida, Spain
- Joint Research Unit CTFC-AGROTECNIO-CERCA Centre, Lleida, Spain
| | - Defu Wang
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems & Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang, China
| | - Nan Zhao
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems & Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang, China
| | - Guomin Huang
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems & Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang, China
| | - Wenfei Liu
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems & Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang, China
| | - Jianping Wu
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
| | - Shuangxi Zhou
- Department of Biological Sciences, Macquarie University, New South Wales, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Richmond, New South Wales, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Richmond, New South Wales, Australia
- Global Centre for Land-based Innovation, Western Sydney University, Hawkesbury Campus, Richmond, New South Wales, Australia
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132
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Wang Y, Xiao J, Li X, Niu S. Global evidence on the asymmetric response of gross primary productivity to interannual precipitation changes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 814:152786. [PMID: 34990664 DOI: 10.1016/j.scitotenv.2021.152786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 12/24/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
Understanding gross primary productivity (GPP) response to precipitation (PPT) changes is essential for predicting land carbon uptake under increasing PPT variability and extremes. Previous studies found that ecosystem GPP may have an asymmetric response to PPT changes, leading to the inconsistency of GPP gains in wet years compared to GPP declines in dry years. However, it is unclear how the asymmetric responses vary among vegetation types and under different PPT variabilities. This study evaluated the global patterns of asymmetries of GPP response to different PPT changes using two state-of-science global GPP datasets. The result shows that under mild PPT changes (|ΔPPT| ≤ 25%), grasslands, savannas, shrublands, and tundra show positive asymmetric responses (i.e., larger GPP gains in wet years than GPP losses in dry years), while other vegetation types show negative asymmetric responses (i.e., larger GPP losses in dry years than GPP gains in wet years). Conversely, all vegetation types show negative GPP asymmetric responses to moderate (25% < |ΔPPT| ≤ 50%) and extreme (|ΔPPT| > 50%) PPT changes. Thus, we propose a new non-linear asymmetric GPP-PPT model that incorporates three modes with regards to vegetation types. Meanwhile, we found that the spatial patterns of asymmetry were mainly driven by PPT amount and variability. Stronger and negative asymmetries were found in areas with smaller PPT amount and variability, while positive asymmetries were found in areas with higher PPT variability. These findings promote our understanding of carbon dynamics under increased PPT variability and extremes and provide new insights for land models to better predict future carbon uptake and its feedback to climate change.
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Affiliation(s)
- Yiheng Wang
- Key Laboratory of Ecosystem Network Observation and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; School of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingfeng Xiao
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA
| | - Xing Li
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Shuli Niu
- Key Laboratory of Ecosystem Network Observation and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; School of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
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133
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Griebel A, Peters JMR, Metzen D, Maier C, Barton CVM, Speckman HN, Boer MM, Nolan RH, Choat B, Pendall E. Tapping into the physiological responses to mistletoe infection during heat and drought stress. TREE PHYSIOLOGY 2022; 42:523-536. [PMID: 34612494 DOI: 10.1093/treephys/tpab113] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Mistletoes are important co-contributors to tree mortality globally, particularly during droughts. In Australia, mistletoe distributions are expanding in temperate woodlands, while their hosts have experienced unprecedented heat and drought stress in recent years. We investigated whether the excessive water use of mistletoes increased the probability of xylem emboli in a mature woodland during the recent record drought that was compounded by multiple heatwaves. We continuously recorded transpiration ($T_{SLA}$) of infected and uninfected branches from two eucalypt species over two summers, monitored stem and leaf water potentials ($\Psi $) and used hydraulic vulnerability curves to estimate percent loss in conductivity (PLC) for each species. Variations in weather (vapor pressure deficit, photosynthetically active radiation, soil water content), host species and % mistletoe foliage explained 78% of hourly $T_{SLA}$. While mistletoe acted as an uncontrollable sink for water in the host even during typical summer days, daily $T_{SLA}$ increased up to 4-fold in infected branches on hot days, highlighting the previously overlooked importance of temperature stress in amplifying water loss in mistletoes. The increased water use of mistletoes resulted in significantly decreased host $\Psi _{\rm{leaf}}$ and $\Psi _{\rm{trunk}}$. It further translated to an estimated increase of up to 11% PLC for infected hosts, confirming greater hydraulic dysfunction of infected trees that place them at higher risk of hydraulic failure. However, uninfected branches of Eucalyptus fibrosa F.Muell. had much tighter controls on water loss than uninfected branches of Eucalyptus moluccana Roxb., which shifted the risk of hydraulic failure towards an increased risk of carbon starvation for E. fibrosa. The contrasting mechanistic responses to heat and drought stress between both co-occurring species demonstrates the complexity of host-parasite interactions and highlights the challenge in predicting species-specific responses to biotic agents in a warmer and drier climate.
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Affiliation(s)
- Anne Griebel
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2571, Australia
| | - Jennifer M R Peters
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2571, Australia
- Climate Change Science Institute & Environmental Science Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831, USA
| | - Daniel Metzen
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2571, Australia
| | - Chelsea Maier
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2571, Australia
| | - Craig V M Barton
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2571, Australia
| | - Heather N Speckman
- Department of Botany, University of Wyoming, 1000 E. Univ. Ave, Laramie, WY 82071, USA
| | - Matthias M Boer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2571, Australia
| | - Rachael H Nolan
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2571, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2571, Australia
| | - Elise Pendall
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2571, Australia
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134
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Giles AL, Rowland L, Bittencourt PRL, Bartholomew DC, Coughlin I, Costa PB, Domingues T, Miatto RC, Barros FV, Ferreira LV, Groenendijk P, Oliveira AAR, da Costa ACL, Meir P, Mencuccini M, Oliveira RS. Small understorey trees have greater capacity than canopy trees to adjust hydraulic traits following prolonged experimental drought in a tropical forest. TREE PHYSIOLOGY 2022; 42:537-556. [PMID: 34508606 DOI: 10.1093/treephys/tpab121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
Future climate change predictions for tropical forests highlight increased frequency and intensity of extreme drought events. However, it remains unclear whether large and small trees have differential strategies to tolerate drought due to the different niches they occupy. The future of tropical forests is ultimately dependent on the capacity of small trees (<10 cm in diameter) to adjust their hydraulic system to tolerate drought. To address this question, we evaluated whether the drought tolerance of neotropical small trees can adjust to experimental water stress and was different from tall trees. We measured multiple drought resistance-related hydraulic traits across nine common neotropical genera at the world's longest-running tropical forest throughfall-exclusion experiment and compared their responses with surviving large canopy trees. Small understorey trees in both the control and the throughfall-exclusion treatment had lower minimum stomatal conductance and maximum hydraulic leaf-specific conductivity relative to large trees of the same genera, as well as a greater hydraulic safety margin (HSM), percentage loss of conductivity and embolism resistance, demonstrating that they occupy a distinct hydraulic niche. Surprisingly, in response to the drought treatment, small trees increased specific hydraulic conductivity by 56.3% and leaf:sapwood area ratio by 45.6%. The greater HSM of small understorey trees relative to large canopy trees likely enabled them to adjust other aspects of their hydraulic systems to increase hydraulic conductivity and take advantage of increases in light availability in the understorey resulting from the drought-induced mortality of canopy trees. Our results demonstrate that differences in hydraulic strategies between small understorey and large canopy trees drive hydraulic niche segregation. Small understorey trees can adjust their hydraulic systems in response to changes in water and light availability, indicating that natural regeneration of tropical forests following long-term drought may be possible.
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Affiliation(s)
- A L Giles
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
| | - L Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - P R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - D C Bartholomew
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - I Coughlin
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900 - Vila Monte Alegre, Ribeirão Preto SP 14040-900, Brazil
- Research School of Biology, Australian National University, 134 Linnaeus Way, Canberra ACT 2601, Australia
| | - P B Costa
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
- Biological Sciences, Stirling Highway, Perth, WA 6009, Australia
| | - T Domingues
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900 - Vila Monte Alegre, Ribeirão Preto SP 14040-900, Brazil
| | - R C Miatto
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900 - Vila Monte Alegre, Ribeirão Preto SP 14040-900, Brazil
| | - F V Barros
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - L V Ferreira
- Museu Paraense Emílio Goeldi, Av. Gov Magalhães Barata, 376 - São Brás, Belém PA 66040-170, Brazil
| | - P Groenendijk
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
| | - A A R Oliveira
- Museu Paraense Emílio Goeldi, Av. Gov Magalhães Barata, 376 - São Brás, Belém PA 66040-170, Brazil
| | - A C L da Costa
- Museu Paraense Emílio Goeldi, Av. Gov Magalhães Barata, 376 - São Brás, Belém PA 66040-170, Brazil
- Biological Sciences, Stirling Highway, Perth, WA 6009, Australia
| | - P Meir
- Research School of Biology, Australian National University, 134 Linnaeus Way, Canberra ACT 2601, Australia
- School of GeoSciences, University of Edinburgh, Drummond St Edinburgh EH9 3FF, UK
| | - M Mencuccini
- CREAF, Campus UAB, Edifici C Campus de Bellaterra Cerdanyola del Vallés 08193, Spain
- ICREA, Passeig de Lluís Companys, 23, Barcelona 08010, Spain
| | - R S Oliveira
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
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135
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Zhou Z, Su P, Wu X, Zhang H, Shi R, Yang J. Leaf and canopy photosynthesis of four desert plants: considering different photosynthetic organs. PHOTOSYNTHESIS RESEARCH 2022; 151:265-277. [PMID: 34780003 DOI: 10.1007/s11120-021-00884-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
Desert plants evolve different photosynthetic organs to adapt to the extreme environment. We studied the leaf and canopy gas exchange, chlorophyll content, fluorescence parameters, and anatomical structure of different photosynthetic organs (leaf and assimilating stem) on four desert plants (Nitraria sphaerocarpa, Caragana korshinskii, Haloxylon ammodendron, and Calligonum mongolicum). The results showed a higher net photosynthetic rate (PN) in the assimilating stems of H. ammodendron and C. mongolicum, which also had a higher light saturation point and a lower light compensation point than leaves (N. sphaerocarpa and C. korshinskii), suggesting more efficient solar energy utilization in the former. Within each species, canopy apparent photosynthetic rate (CAP) was significantly lower than PN, and the daily average CAP of the assimilating stems was significantly higher than leaves. These findings indicated that the photosynthetic response of desert plants was specific to photosynthetic organs. We concluded that the assimilating stem was a superior adaption for desert plants to survive the arid environments.
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Affiliation(s)
- Zijuan Zhou
- Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
| | - Peixi Su
- Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Xiukun Wu
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resource, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Haina Zhang
- School of Water Resources and Ecological Engineering, Nanchang Institute of Technology, Nanchang, 330099, China
| | - Rui Shi
- Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Jianping Yang
- Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
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136
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Britton TG, Brodribb TJ, Richards SA, Ridley C, Hovenden MJ. Canopy damage during a natural drought depends on species identity, physiology and stand composition. THE NEW PHYTOLOGIST 2022; 233:2058-2070. [PMID: 34850394 DOI: 10.1111/nph.17888] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/21/2021] [Indexed: 06/13/2023]
Abstract
Vulnerability to xylem cavitation is a strong predictor of drought-induced damage in forest communities. However, biotic features of the community itself can influence water availability at the individual tree-level, thereby modifying patterns of drought damage. Using an experimental forest in Tasmania, Australia, we determined the vulnerability to cavitation (leaf P50 ) of four tree species and assessed the drought-induced canopy damage of 2944 6-yr-old trees after an extreme natural drought episode. We examined how individual damage was related to their size and the density and species identity of neighbouring trees. The two co-occurring dominant tree species, Eucalyptus delegatensis and Eucalyptus regnans, were the most vulnerable to drought-induced xylem cavitation and both species suffered significantly greater damage than neighbouring, subdominant species Pomaderris apetala and Acacia dealbata. While the two eucalypts had similar leaf P50 values, E. delegatensis suffered significantly greater damage, which was strongly related to the density of neighbouring P. apetala. Damage in E. regnans was less impacted by neighbouring plants and smaller trees of both eucalypts sustained significantly more damage than larger trees. Our findings demonstrate that natural drought damage is influenced by individual plant physiology as well as the composition, physiology and density of the surrounding stand.
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Affiliation(s)
- Travis G Britton
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
- ARC Training Centre for Forest Value, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Timothy J Brodribb
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Shane A Richards
- School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Chantelle Ridley
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Mark J Hovenden
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
- ARC Training Centre for Forest Value, University of Tasmania, Hobart, Tas., 7001, Australia
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137
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Weithmann G, Link RM, Banzragch BE, Würzberg L, Leuschner C, Schuldt B. Soil water availability and branch age explain variability in xylem safety of European beech in Central Europe. Oecologia 2022; 198:629-644. [PMID: 35212818 PMCID: PMC8956530 DOI: 10.1007/s00442-022-05124-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 01/24/2022] [Indexed: 12/17/2022]
Abstract
Xylem embolism resistance has been identified as a key trait with a causal relation to drought-induced tree mortality, but not much is known about its intra-specific trait variability (ITV) in dependence on environmental variation. We measured xylem safety and efficiency in 300 European beech (Fagus sylvatica L.) trees across 30 sites in Central Europe, covering a precipitation reduction from 886 to 522 mm year−1. A broad range of variables that might affect embolism resistance in mature trees, including climatic and soil water availability, competition, and branch age, were examined. The average P50 value varied by up to 1 MPa between sites. Neither climatic aridity nor structural variables had a significant influence on P50. However, P50 was less negative for trees with a higher soil water storage capacity, and positively related to branch age, while specific conductivity (Ks) was not significantly associated with either of these variables. The greatest part of the ITV for xylem safety and efficiency was attributed to random variability within populations. We conclude that the influence of site water availability on P50 and Ks is low in European beech, and that the high degree of within-population variability for P50, partly due to variation in branch age, hampers the identification of a clear environmental signal.
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Affiliation(s)
- Greta Weithmann
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany
| | - Roman M Link
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany.,Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz, 97082, Würzburg, Germany
| | - Bat-Enerel Banzragch
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany
| | - Laura Würzberg
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany
| | - Christoph Leuschner
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany.,Centre for Biodiversity and Sustainable Land Use (CBL), University of Goettingen, 37075, Göttingen, Germany
| | - Bernhard Schuldt
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany. .,Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz, 97082, Würzburg, Germany.
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138
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Cocozza C, Penna D. Towards a more active dialogue between hydrologists and ecophysiologists for interdisciplinary studies in forest ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:150877. [PMID: 34627886 DOI: 10.1016/j.scitotenv.2021.150877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 10/01/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
Understanding the internal functioning of natural systems often requires interdisciplinary approaches and competences that allow encompassing and disentangling different and strictly intertwined physical and biological processes. Hydrology and ecophysiology are examples of complementary and highly interconnected disciplines that share water as a common analysis element when investigating the functioning of vegetated ecosystems. In this discussion paper, we call for more frequent and active dialogue and collaboration between (field) hydrologists and ecophysiologists to study natural processes at the boundary between the two disciplines. We report some examples of the specific approaches of hydrologists and ecophysiologists to analyse water movement in the soil-vegetation-atmosphere continuum at increasing spatial scales, highlighting how the same mechanisms can be seen from different, but largely complementary, points of view. We argue that these different perspectives can and should be merged in order to overcome possibly fragmented vision of complex processes and provide a more holistic comprehension of ecohydrological mechanisms in forest ecosystems.
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Affiliation(s)
- Claudia Cocozza
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Via San Bonaventura 13, 50145 Florence, Italy
| | - Daniele Penna
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Via San Bonaventura 13, 50145 Florence, Italy.
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139
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Nie ZF, Liao ZQ, Yao GQ, Tian XQ, Bi MH, Teixeira da Silva JA, Gao TP, Fang XW. Divergent stem hydraulic strategies of Caragana korshinskii resprouts following a disturbance. TREE PHYSIOLOGY 2022; 42:325-336. [PMID: 34387352 DOI: 10.1093/treephys/tpab108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
Resprouting plants are distributed in many vegetation communities worldwide. With increasing resprout age post-severe-disturbance, new stems grow rapidly at their early age, and decrease in their growth with gradually decreasing water status thereafter. However, there is little knowledge about how stem hydraulic strategies and anatomical traits vary post-disturbance. In this study, the stem water potential (Ψstem), maximum stem hydraulic conductivity (Kstem-max), water potential at 50% loss of hydraulic conductivity (Kstem P50) and anatomical traits of Caragana korshinkii resprouts were measured during a 1- to 13-year post-disturbance period. We found that the Kstem-max decreased with resprout age from 1-year-old resprouts (84.2 mol m-1 s-1 MPa-1) to 13-year-old resprouts (54.2 mol m-1 s-1 MPa-1) as a result of decreases in the aperture fraction (Fap) and the sum of aperture area on per unit intervessel wall area (Aap). The Kstem P50 of the resprouts decreased from 1-year-old resprouts (-1.8 MPa) to 13-year-old resprouts (-2.9 MPa) as a result of increases in vessel implosion resistance (t/b)2, wood density (WD), vessel grouping index (GI) and decreases in Fap and Aap. These shifts in hydraulic structure and function resulted in an age-based divergence in hydraulic strategies i.e., a change from an acquisitive strategy to a conservative strategy, with increasing resprout age post-disturbance.
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Affiliation(s)
- Zheng-Fei Nie
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Zhong-Qiang Liao
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Guang-Qian Yao
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xue-Qian Tian
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Min-Hui Bi
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | | | - Tian-Peng Gao
- School of Biological and Environmental Engineering, Xi'an University, Xi'an 710065, China
| | - Xiang-Wen Fang
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
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140
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Rao K, Williams AP, Diffenbaugh NS, Yebra M, Konings AG. Plant-water sensitivity regulates wildfire vulnerability. Nat Ecol Evol 2022; 6:332-339. [PMID: 35132185 PMCID: PMC8913365 DOI: 10.1038/s41559-021-01654-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/17/2021] [Indexed: 11/16/2022]
Abstract
Extreme wildfires extensively impact human health and the environment. Increasing vapour pressure deficit (VPD) has led to a chronic increase in wildfire area in the western United States, yet some regions have been more affected than others. Here we show that for the same increase in VPD, burned area increases more in regions where vegetation moisture shows greater sensitivity to water limitation (plant-water sensitivity; R2 = 0.71). This has led to rapid increases in human exposure to wildfire risk, both because the population living in areas with high plant-water sensitivity grew 50% faster during 1990–2010 than in other wildland–urban interfaces and because VPD has risen most rapidly in these vulnerable areas. As plant-water sensitivity is strongly linked to wildfire vulnerability, accounting for ecophysiological controls should improve wildfire forecasts. If recent trends in VPD and demographic shifts continue, human wildfire risk will probably continue to increase. The authors show that an ecosystem’s sensitivity to drought, measured as the amount of change in vegetation moisture content for a given change in background moisture, predicts the fire hazard in that location.
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141
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Bauman D, Fortunel C, Cernusak LA, Bentley LP, McMahon SM, Rifai SW, Aguirre-Gutiérrez J, Oliveras I, Bradford M, Laurance SGW, Delhaye G, Hutchinson MF, Dempsey R, McNellis BE, Santos-Andrade PE, Ninantay-Rivera HR, Chambi Paucar JR, Phillips OL, Malhi Y. Tropical tree growth sensitivity to climate is driven by species intrinsic growth rate and leaf traits. GLOBAL CHANGE BIOLOGY 2022; 28:1414-1432. [PMID: 34741793 DOI: 10.1111/gcb.15982] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 10/26/2021] [Indexed: 06/13/2023]
Abstract
A better understanding of how climate affects growth in tree species is essential for improved predictions of forest dynamics under climate change. Long-term climate averages (mean climate) drive spatial variations in species' baseline growth rates, whereas deviations from these averages over time (anomalies) can create growth variation around the local baseline. However, the rarity of long-term tree census data spanning climatic gradients has so far limited our understanding of their respective role, especially in tropical systems. Furthermore, tree growth sensitivity to climate is likely to vary widely among species, and the ecological strategies underlying these differences remain poorly understood. Here, we utilize an exceptional dataset of 49 years of growth data for 509 tree species across 23 tropical rainforest plots along a climatic gradient to examine how multiannual tree growth responds to both climate means and anomalies, and how species' functional traits mediate these growth responses to climate. We show that anomalous increases in atmospheric evaporative demand and solar radiation consistently reduced tree growth. Drier forests and fast-growing species were more sensitive to water stress anomalies. In addition, species traits related to water use and photosynthesis partly explained differences in growth sensitivity to both climate means and anomalies. Our study demonstrates that both climate means and anomalies shape tree growth in tropical forests and that species traits can provide insights into understanding these demographic responses to climate change, offering a promising way forward to forecast tropical forest dynamics under different climate trajectories.
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Affiliation(s)
- David Bauman
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
- Smithsonian Environmental Research Center, Edgewater, Maryland, USA
- AMAP (Botanique et Modélisation de l'Architecture des Plantes et des Végétations), Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France
| | - Claire Fortunel
- AMAP (Botanique et Modélisation de l'Architecture des Plantes et des Végétations), Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France
| | - Lucas A Cernusak
- Centre for Tropical Environmental and Sustainability Science, College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Lisa P Bentley
- Department of Biology, Sonoma State University, Rohnert Park, California, USA
| | - Sean M McMahon
- Smithsonian Environmental Research Center, Edgewater, Maryland, USA
| | - Sami W Rifai
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
- ARC Centre of Excellence for Climate Extremes, University of New South Wales, Sydney, New South Wales, Australia
- Department of Environmental Science, Policy and Management, UC Berkeley, Berkeley, California, USA
| | - Jesús Aguirre-Gutiérrez
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
- Biodiversity Dynamics, Naturalis Biodiversity Center, Leiden, The Netherlands
| | - Imma Oliveras
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Matt Bradford
- CSIRO Land and Water, Tropical Forest Research Centre, Atherton, Queensland, Australia
| | - Susan G W Laurance
- Centre for Tropical Environmental and Sustainability Science, College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Guillaume Delhaye
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Michael F Hutchinson
- Fenner School of Environment and Society, The Australian National University, Canberra, Australia
| | - Raymond Dempsey
- Centre for Tropical Environmental and Sustainability Science, College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Brandon E McNellis
- Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, New Mexico, USA
| | | | | | | | | | - Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
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142
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Marchin RM, Backes D, Ossola A, Leishman MR, Tjoelker MG, Ellsworth DS. Extreme heat increases stomatal conductance and drought-induced mortality risk in vulnerable plant species. GLOBAL CHANGE BIOLOGY 2022; 28:1133-1146. [PMID: 34741566 PMCID: PMC9299030 DOI: 10.1111/gcb.15976] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/12/2021] [Accepted: 10/27/2021] [Indexed: 05/29/2023]
Abstract
Tree mortality during global-change-type drought is usually attributed to xylem dysfunction, but as climate change increases the frequency of extreme heat events, it is necessary to better understand the interactive role of heat stress. We hypothesized that some drought-stressed plants paradoxically open stomata in heatwaves to prevent leaves from critically overheating. We experimentally imposed heat (>40°C) and drought stress onto 20 broadleaf evergreen tree/shrub species in a glasshouse study. Most well-watered plants avoided lethal overheating, but drought exacerbated thermal damage during heatwaves. Thermal safety margins (TSM) quantifying the difference between leaf surface temperature and leaf critical temperature, where photosynthesis is disrupted, identified species vulnerability to heatwaves. Several mechanisms contributed to high heat tolerance and avoidance of damaging leaf temperatures-small leaf size, low leaf osmotic potential, high leaf mass per area (i.e., thick, dense leaves), high transpirational capacity, and access to water. Water-stressed plants had smaller TSM, greater crown dieback, and a fundamentally different stomatal heatwave response relative to well-watered plants. On average, well-watered plants closed stomata and decreased stomatal conductance (gs ) during the heatwave, but droughted plants did not. Plant species with low gs , either due to isohydric stomatal behavior under water deficit or inherently low transpirational capacity, opened stomata and increased gs under high temperatures. The current paradigm maintains that stomata close before hydraulic thresholds are surpassed, but our results suggest that isohydric species may dramatically increase gs (over sixfold increases) even past their leaf turgor loss point. By actively increasing water loss at high temperatures, plants can be driven toward mortality thresholds more rapidly than has been previously recognized. The inclusion of TSM and responses to heat stress could improve our ability to predict the vulnerability of different tree species to future droughts.
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Affiliation(s)
- Renée M. Marchin
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Diana Backes
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Alessandro Ossola
- Department of Biological SciencesMacquarie UniversityNorth RydeNew South WalesAustralia
| | - Michelle R. Leishman
- Department of Biological SciencesMacquarie UniversityNorth RydeNew South WalesAustralia
| | - Mark G. Tjoelker
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNew South WalesAustralia
| | - David S. Ellsworth
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNew South WalesAustralia
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143
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Sire L, Yáñez PS, Wang C, Bézier A, Courtial B, Cours J, Fontaneto D, Larrieu L, Bouget C, Thorn S, Müller J, Yu DW, Monaghan MT, Herniou EA, Lopez-Vaamonde C. Climate-induced forest dieback drives compositional changes in insect communities that are more pronounced for rare species. Commun Biol 2022; 5:57. [PMID: 35042989 PMCID: PMC8766456 DOI: 10.1038/s42003-021-02968-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 12/07/2021] [Indexed: 12/26/2022] Open
Abstract
Species richness, abundance and biomass of insects have recently undergone marked declines in Europe. We metabarcoded 211 Malaise-trap samples to investigate whether drought-induced forest dieback and subsequent salvage logging had an impact on ca. 3000 species of flying insects in silver fir Pyrenean forests. While forest dieback had no measurable impact on species richness, there were significant changes in community composition that were consistent with those observed during natural forest succession. Importantly, most observed changes were driven by rare species. Variation was explained primarily by canopy openness at the local scale, and the tree-related microhabitat diversity and deadwood amount at landscape scales. The levels of salvage logging in our study did not explain compositional changes. We conclude that forest dieback drives changes in species assemblages that mimic natural forest succession, and markedly increases the risk of catastrophic loss of rare species through homogenization of environmental conditions.
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Affiliation(s)
- Lucas Sire
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR 7261, CNRS-Université de Tours, Tours, France.
| | - Paul Schmidt Yáñez
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301, 12587, Berlin, Germany
| | - Cai Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Kunming College of Life Sciences, University of Chinese Academy of Sciences, Kunming, China
| | - Annie Bézier
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR 7261, CNRS-Université de Tours, Tours, France
| | | | - Jérémy Cours
- INRAE 'Forest Ecosystems' Research Unit - Biodiversity team Domaine des Barres, F-45290, Nogent-sur-Vernisson, France
| | - Diego Fontaneto
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Largo Tonolli 50, 28922, Verbania Pallanza, Italy
| | - Laurent Larrieu
- Université de Toulouse, INRAE, UMR DYNAFOR, Castanet-Tolosan, France
- CRPF Occitanie, Tarbes, France
| | - Christophe Bouget
- INRAE 'Forest Ecosystems' Research Unit - Biodiversity team Domaine des Barres, F-45290, Nogent-sur-Vernisson, France
| | - Simon Thorn
- Field Station Fabrikschleichach, Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Glashüttenstraße 5, 96181, Rauhenebrach, Germany
| | - Jörg Müller
- Field Station Fabrikschleichach, Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Glashüttenstraße 5, 96181, Rauhenebrach, Germany
- Bavarian Forest National Park, Freyunger Str. 2, 94481, Grafenau, Germany
| | - Douglas W Yu
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR47TJ, UK
| | - Michael T Monaghan
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301, 12587, Berlin, Germany
- Institut für Biologie, Freie Universität Berlin, Königin-Luise-Straße. 1-3, 12489, Berlin, Germany
| | - Elisabeth A Herniou
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR 7261, CNRS-Université de Tours, Tours, France
| | - Carlos Lopez-Vaamonde
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR 7261, CNRS-Université de Tours, Tours, France
- INRAE, Zoologie Forestière, F-45075, Orléans, France
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144
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Zhang YB, Yang D, Zhang KY, Bai XL, Wang YSD, Wu HD, Ding LZ, Zhang YJ, Zhang JL. Higher water and nutrient use efficiencies in savanna than in rainforest lianas result in no difference in photosynthesis. TREE PHYSIOLOGY 2022; 42:145-159. [PMID: 34312678 PMCID: PMC8755031 DOI: 10.1093/treephys/tpab099] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 07/07/2021] [Indexed: 05/25/2023]
Abstract
Differences in traits between lianas and trees in tropical forests have been studied extensively; however, few have compared the ecological strategies of lianas from different habitats. Here, we measured 25 leaf and stem traits concerning leaf anatomy, morphology, physiology and stem hydraulics for 17 liana species from a tropical seasonal rainforest and for 19 liana species from a valley savanna in south-west China. We found that savanna lianas had higher vessel density, wood density and lower hydraulically weighted vessel diameter and theoretical hydraulic conductivity than tropical seasonal rainforest lianas. Compared with tropical seasonal rainforest lianas, savanna lianas also showed higher leaf dry matter content, carbon isotope composition (δ13C), photosynthetic water use efficiency, ratio of nitrogen to phosphorus, photosynthetic phosphorus use efficiency and lower leaf size, stomatal conductance and nitrogen, phosphorus and potassium concentrations. Interestingly, no differences in light-saturated photosynthetic rate were found between savanna and tropical seasonal rainforest lianas either on mass or area basis. This is probably due to the higher water and nutrient use efficiencies of savanna lianas. A principal component analysis revealed that savanna and tropical seasonal rainforest lianas were significantly separated along the first axis, which was strongly associated with acquisitive or conservative resource use strategy. Leaf and stem functional traits were coordinated across lianas, but the coordination or trade-off was stronger in the savanna than in the tropical seasonal rainforest. In conclusion, a relatively conservative (slow) strategy concerning water and nutrient use may benefit the savanna lianas, while higher nutrient and water use efficiencies allow them to maintain similar photosynthesis as tropical seasonal rainforest species. Our results clearly showed divergences in functional traits between lianas from savanna and tropical seasonal rainforest, suggesting that enhanced water and nutrient use efficiencies might contribute to the distribution of lianas in savanna ecosystems.
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Affiliation(s)
- Yun-Bing Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Da Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
| | - Ke-Yan Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Xiao-Long Bai
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Yang-Si-Ding Wang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Huai-Dong Wu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
| | - Ling-Zi Ding
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, ME 04469, USA
| | - Jiao-Lin Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- Yuanjiang Savanna Ecosystem Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yuanjiang, Yunnan 653300, China
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145
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Gardner A, Ellsworth DS, Crous KY, Pritchard J, MacKenzie AR. Is photosynthetic enhancement sustained through three years of elevated CO2 exposure in 175-year-old Quercus robur? TREE PHYSIOLOGY 2022; 42:130-144. [PMID: 34302175 PMCID: PMC8754963 DOI: 10.1093/treephys/tpab090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 07/07/2021] [Indexed: 05/15/2023]
Abstract
Current carbon cycle models attribute rising atmospheric CO2 as the major driver of the increased terrestrial carbon sink, but with substantial uncertainties. The photosynthetic response of trees to elevated atmospheric CO2 is a necessary step, but not the only one, for sustaining the terrestrial carbon uptake, but can vary diurnally, seasonally and with duration of CO2 exposure. Hence, we sought to quantify the photosynthetic response of the canopy-dominant species, Quercus robur, in a mature deciduous forest to elevated CO2 (eCO2) (+150 μmol mol-1 CO2) over the first 3 years of a long-term free air CO2 enrichment facility at the Birmingham Institute of Forest Research in central England (BIFoR FACE). Over 3000 measurements of leaf gas exchange and related biochemical parameters were conducted in the upper canopy to assess the diurnal and seasonal responses of photosynthesis during the 2nd and 3rd year of eCO2 exposure. Measurements of photosynthetic capacity via biochemical parameters, derived from CO2 response curves, (Vcmax and Jmax) together with leaf nitrogen concentrations from the pre-treatment year to the 3rd year of eCO2 exposure, were examined. We hypothesized an initial enhancement in light-saturated net photosynthetic rates (Asat) with CO2 enrichment of ≈37% based on theory but also expected photosynthetic capacity would fall over the duration of the study. Over the 3-year period, Asat of upper-canopy leaves was 33 ± 8% higher (mean and standard error) in trees grown in eCO2 compared with ambient CO2 (aCO2), and photosynthetic enhancement decreased with decreasing light. There were no significant effects of CO2 treatment on Vcmax or Jmax, nor leaf nitrogen. Our results suggest that mature Q. robur may exhibit a sustained, positive response to eCO2 without photosynthetic downregulation, suggesting that, with adequate nutrients, there will be sustained enhancement in C assimilated by these mature trees. Further research will be required to understand the location and role of the additionally assimilated carbon.
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Affiliation(s)
- A Gardner
- Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, B15 2TT, UK
- School of Biological Sciences, University of Birmingham, Edgbaston, B15 2TT, UK
| | - D S Ellsworth
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW 2751, Australia
| | - K Y Crous
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW 2751, Australia
| | - J Pritchard
- Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, B15 2TT, UK
- School of Biological Sciences, University of Birmingham, Edgbaston, B15 2TT, UK
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146
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Trueba S, Théroux-Rancourt G, Earles JM, Buckley TN, Love D, Johnson DM, Brodersen C. The three-dimensional construction of leaves is coordinated with water use efficiency in conifers. THE NEW PHYTOLOGIST 2022; 233:851-861. [PMID: 34614205 DOI: 10.1111/nph.17772] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
Conifers prevail in the canopies of many terrestrial biomes, holding a great ecological and economic importance globally. Current increases in temperature and aridity are imposing high transpirational demands and resulting in conifer mortality. Therefore, identifying leaf structural determinants of water use efficiency is essential for predicting physiological impacts due to environmental variation. Using synchrotron-generated microtomography imaging, we extracted leaf volumetric anatomy and stomatal traits in 34 species across conifers with a special focus on Pinus, the richest conifer genus. We show that intrinsic water use efficiency (WUEi ) is positively driven by leaf vein volume. Needle-like leaves of Pinus, as opposed to flat leaves or flattened needles of other genera, showed lower mesophyll porosity, decreasing the relative mesophyll volume. This led to increased ratios of stomatal pore number per mesophyll or intercellular airspace volume, which emerged as powerful explanatory variables, predicting both stomatal conductance and WUEi . Our results clarify how the three-dimensional organisation of tissues within the leaf has a direct impact on plant water use and carbon uptake. By identifying a suite of structural traits that influence important physiological functions, our findings can help to understand how conifers may respond to the pressures exerted by climate change.
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Affiliation(s)
- Santiago Trueba
- School of the Environment, Yale University, New Haven, CT, 06511, USA
- University of Bordeaux, INRAE, UMR BIOGECO, Pessac, 33615, France
| | - Guillaume Théroux-Rancourt
- University of Natural Resources and Life Sciences, Vienna, Department of Integrative Biology and Biodiversity Research, Institute of Botany, Vienna, 1180, Austria
| | - J Mason Earles
- Department of Viticulture and Enology, University of California, Davis, CA, 95616, USA
| | - Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, CA, 95916, USA
| | - David Love
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT, 06511, USA
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147
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Harrison Day BL, Carins-Murphy MR, Brodribb TJ. Reproductive water supply is prioritized during drought in tomato. PLANT, CELL & ENVIRONMENT 2022; 45:69-79. [PMID: 34705293 DOI: 10.1111/pce.14206] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 10/09/2021] [Accepted: 10/10/2021] [Indexed: 06/13/2023]
Abstract
Reproductive success largely defines the fitness of plant species. Understanding how heat and drought affect plant reproduction is thus key to predicting future plant fitness under rising global temperatures. Recent work suggests reproductive tissues are highly vulnerable to water stress in perennial plants where reproductive sacrifice could preserve plant survival. However, most crop species are annuals where such a strategy would theoretically reduce fitness. We examined the reproductive strategy of tomato (Solanum lycopersicum var. Rheinlands Ruhm) to determine whether water supply to fruits is prioritized above vegetative tissues during drought. Using optical methods, we mapped xylem cavitation and tissue shrinkage in vegetative and reproductive organs during dehydration to determine the priority of water flow under acute water stress. Stems and peduncles of tomato showed significantly greater xylem cavitation resistance than leaves. This maintenance of intact water supply enabled tomato fruit to continue to expand during acute water stress, utilizing xylem water made available by tissue collapse and early cavitation of leaves. Here, tomato plants prioritize water supply to reproductive tissues, maintaining fruit development under drought conditions. These results emphasize the critical role of water transport in shaping life history and suggest a broad relevance of hydraulic prioritization in plant ecology.
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Affiliation(s)
| | | | - Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
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148
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De Pauw K, Sanczuk P, Meeussen C, Depauw L, De Lombaerde E, Govaert S, Vanneste T, Brunet J, Cousins SAO, Gasperini C, Hedwall PO, Iacopetti G, Lenoir J, Plue J, Selvi F, Spicher F, Uria-Diez J, Verheyen K, Vangansbeke P, De Frenne P. Forest understorey communities respond strongly to light in interaction with forest structure, but not to microclimate warming. THE NEW PHYTOLOGIST 2022; 233:219-235. [PMID: 34664731 DOI: 10.1111/nph.17803] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
Forests harbour large spatiotemporal heterogeneity in canopy structure. This variation drives the microclimate and light availability at the forest floor. So far, we do not know how light availability and sub-canopy temperature interactively mediate the impact of macroclimate warming on understorey communities. We therefore assessed the functional response of understorey plant communities to warming and light addition in a full factorial experiment installed in temperate deciduous forests across Europe along natural microclimate, light and macroclimate gradients. Furthermore, we related these functional responses to the species' life-history syndromes and thermal niches. We found no significant community responses to the warming treatment. The light treatment, however, had a stronger impact on communities, mainly due to responses by fast-colonizing generalists and not by slow-colonizing forest specialists. The forest structure strongly mediated the response to light addition and also had a clear impact on functional traits and total plant cover. The effects of short-term experimental warming were small and suggest a time-lag in the response of understorey species to climate change. Canopy disturbance, for instance due to drought, pests or logging, has a strong and immediate impact and particularly favours generalists in the understorey in structurally complex forests.
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Affiliation(s)
- Karen De Pauw
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Pieter Sanczuk
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Camille Meeussen
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Leen Depauw
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Emiel De Lombaerde
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Sanne Govaert
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Thomas Vanneste
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Jörg Brunet
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 190, 234 22, Lomma, Sweden
| | - Sara A O Cousins
- Landscapes, Environment and Geomatics, Department of Physical Geography, Stockholm University, Svante Arrhenius väg 8, 106 91, Stockholm, Sweden
| | - Cristina Gasperini
- Department of Agriculture, Food, Environment and Forestry, University of Florence, P. le Cascine 28, 50144, Florence, Italy
| | - Per-Ola Hedwall
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 190, 234 22, Lomma, Sweden
| | - Giovanni Iacopetti
- Department of Agriculture, Food, Environment and Forestry, University of Florence, P. le Cascine 28, 50144, Florence, Italy
| | - Jonathan Lenoir
- UMR CNRS 7058 'Ecologie et Dynamique des Systèmes Anthropisés' (EDYSAN), Université de Picardie Jules Verne, 1 Rue des Louvels, 80000, Amiens, France
| | - Jan Plue
- IVL Swedish Environmental Institute, Valhallavägen 81, 114 28, Stockholm, Sweden
| | - Federico Selvi
- Department of Agriculture, Food, Environment and Forestry, University of Florence, P. le Cascine 28, 50144, Florence, Italy
| | - Fabien Spicher
- UMR CNRS 7058 'Ecologie et Dynamique des Systèmes Anthropisés' (EDYSAN), Université de Picardie Jules Verne, 1 Rue des Louvels, 80000, Amiens, France
| | - Jaime Uria-Diez
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 190, 234 22, Lomma, Sweden
| | - Kris Verheyen
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Pieter Vangansbeke
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Pieter De Frenne
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
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149
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Cernusak LA, De Kauwe MG. Red light shines a path forward on leaf minimum conductance. THE NEW PHYTOLOGIST 2022; 233:5-7. [PMID: 34714941 DOI: 10.1111/nph.17794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/11/2021] [Indexed: 06/13/2023]
Affiliation(s)
- Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Qld, 4878, Australia
| | - Martin G De Kauwe
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
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150
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Johnson KM, Lucani C, Brodribb TJ. In vivo monitoring of drought-induced embolism in Callitris rhomboidea trees reveals wide variation in branchlet vulnerability and high resistance to tissue death. THE NEW PHYTOLOGIST 2022; 233:207-218. [PMID: 34625973 DOI: 10.1111/nph.17786] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
Damage to the plant water transport system through xylem cavitation is known to be a driver of plant death in drought conditions. However, a lack of techniques to continuously monitor xylem embolism in whole plants in vivo has hampered our ability to investigate both how this damage propagates and the possible mechanistic link between xylem damage and tissue death. Using optical and fluorescence sensors, we monitored drought-induced xylem embolism accumulation and photosynthetic damage in vivo throughout the canopy of a drought-resistant conifer, Callitris rhomboidea, during drought treatments of c. 1 month duration. We show that drought-induced damage to the xylem can be monitored in vivo in whole trees during extended periods of water stress. Under these conditions, vulnerability of the xylem to cavitation varied widely among branchlets, with photosynthetic damage only recorded once > 90% of the xylem was cavitated. The variation in branchlet vulnerability has important implications for understanding how trees like C. rhomboidea survive drought, and the high resistance of branchlets to tissue damage points to runaway cavitation as a likely driver of tissue death in C. rhomboidea branch tips.
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Affiliation(s)
- Kate M Johnson
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Christopher Lucani
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Timothy J Brodribb
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
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