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Matos IS, McDonough S, Johnson BC, Kalantar D, Rohde J, Sahu R, Wang J, Fontao A, To J, Carlos S, Garcia L, Boakye M, Forbes H, Blonder BW. Negative allometry of leaf xylem conduit diameter and double-wall thickness: implications for implosion safety. New Phytol 2024; 242:2464-2478. [PMID: 38641796 DOI: 10.1111/nph.19771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 03/25/2024] [Indexed: 04/21/2024]
Abstract
Xylem conduits have lignified walls to resist crushing pressures. The thicker the double-wall (T) relative to its diameter (D), the greater the implosion safety. Having safer conduits may incur higher costs and reduced flow, while having less resistant xylem may lead to catastrophic collapse under drought. Although recent studies have shown that conduit implosion commonly occurs in leaves, little is known about how leaf xylem scales T vs D to trade off safety, flow efficiency, mechanical support, and cost. We measured T and D in > 7000 conduits of 122 species to investigate how T vs D scaling varies across clades, habitats, growth forms, leaf, and vein sizes. As conduits become wider, their double-cell walls become proportionally thinner, resulting in a negative allometry between T and D. That is, narrower conduits, which are usually subjected to more negative pressures, are proportionally safer than wider ones. Higher implosion safety (i.e. higher T/D ratios) was found in asterids, arid habitats, shrubs, small leaves, and minor veins. Despite the strong allometry, implosion safety does not clearly trade off with other measured leaf functions, suggesting that implosion safety at whole-leaf level cannot be easily predicted solely by individual conduits' anatomy.
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Affiliation(s)
- Ilaine Silveira Matos
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Samantha McDonough
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Breanna Carrillo Johnson
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Diana Kalantar
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - James Rohde
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Roshni Sahu
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Joyce Wang
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Adrian Fontao
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Jason To
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Sonoma Carlos
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Lisa Garcia
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Mickey Boakye
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Holly Forbes
- University of California Botanical Garden, Berkeley, CA, 94720, USA
| | - Benjamin Wong Blonder
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
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2
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Huang J, Ladd SN, Ingrisch J, Kübert A, Meredith LK, van Haren J, Bamberger I, Daber LE, Kühnhammer K, Bailey K, Hu J, Fudyma J, Shi L, Dippold MA, Meeran K, Miller L, O'Brien MJ, Yang H, Herrera-Ramírez D, Hartmann H, Trumbore S, Bahn M, Werner C, Lehmann MM. The mobilization and transport of newly fixed carbon are driven by plant water use in an experimental rainforest under drought. J Exp Bot 2024; 75:2545-2557. [PMID: 38271585 DOI: 10.1093/jxb/erae030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 01/24/2024] [Indexed: 01/27/2024]
Abstract
Non-structural carbohydrates (NSCs) are building blocks for biomass and fuel metabolic processes. However, it remains unclear how tropical forests mobilize, export, and transport NSCs to cope with extreme droughts. We combined drought manipulation and ecosystem 13CO2 pulse-labeling in an enclosed rainforest at Biosphere 2, assessed changes in NSCs, and traced newly assimilated carbohydrates in plant species with diverse hydraulic traits and canopy positions. We show that drought caused a depletion of leaf starch reserves and slowed export and transport of newly assimilated carbohydrates below ground. Drought effects were more pronounced in conservative canopy trees with limited supply of new photosynthates and relatively constant water status than in those with continual photosynthetic supply and deteriorated water status. We provide experimental evidence that local utilization, export, and transport of newly assimilated carbon are closely coupled with plant water use in canopy trees. We highlight that these processes are critical for understanding and predicting tree resistance and ecosystem fluxes in tropical forest under drought.
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Affiliation(s)
- Jianbei Huang
- Max Planck Institute for Biogeochemistry, D-07745 Jena, Germany
| | - S Nemiah Ladd
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
- Department of Environmental Sciences, University of Basel, Bernoullistrasse 30, 4056 Basel, Switzerland
| | - Johannes Ingrisch
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
- Department of Ecology, University of Innsbruck, Sternwartestr 15, 6020 Innsbruck, Austria
| | - Angelika Kübert
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
| | - Laura K Meredith
- School of Natural Resources and the Environment, University of Arizona, 1064 E. Lowell St., Tucson, AZ 85721, USA
- Biosphere 2, University of Arizona, 32540 S. Biosphere Rd, Oracle, AZ 85739, USA
| | - Joost van Haren
- Biosphere 2, University of Arizona, 32540 S. Biosphere Rd, Oracle, AZ 85739, USA
- Honors College, University of Arizona, 1101 East Mabel Street, Tucson, AZ 85719, USA
| | - Ines Bamberger
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
- Atmospheric Chemistry Group, University of Bayreuth (BayCEER), Germany
| | - L Erik Daber
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
| | - Kathrin Kühnhammer
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
| | - Kinzie Bailey
- School of Natural Resources and the Environment, University of Arizona, 1064 E. Lowell St., Tucson, AZ 85721, USA
| | - Jia Hu
- School of Natural Resources and the Environment, University of Arizona, 1064 E. Lowell St., Tucson, AZ 85721, USA
| | - Jane Fudyma
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA
- Department of Land, Air, and Water Resources, University of California, Davis, CA, USA
| | - Lingling Shi
- Biogeochemistry of Agroecosystems, University of Göttingen, Göttingen, Germany
- Geo-Biosphere Interactions, University of Tuebingen, Tuebingen, Germany
| | - Michaela A Dippold
- Biogeochemistry of Agroecosystems, University of Göttingen, Göttingen, Germany
- Geo-Biosphere Interactions, University of Tuebingen, Tuebingen, Germany
| | - Kathiravan Meeran
- Department of Ecology, University of Innsbruck, Sternwartestr 15, 6020 Innsbruck, Austria
| | - Luke Miller
- Biosphere 2, University of Arizona, 32540 S. Biosphere Rd, Oracle, AZ 85739, USA
| | - Michael J O'Brien
- Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, Almería, Spain
| | - Hui Yang
- Max Planck Institute for Biogeochemistry, D-07745 Jena, Germany
| | | | - Henrik Hartmann
- Max Planck Institute for Biogeochemistry, D-07745 Jena, Germany
- Institute for Forest Protection, Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Erwin-Baur-Straße 27, D-06484 Quedlinburg, Germany
| | - Susan Trumbore
- Max Planck Institute for Biogeochemistry, D-07745 Jena, Germany
| | - Michael Bahn
- Department of Ecology, University of Innsbruck, Sternwartestr 15, 6020 Innsbruck, Austria
| | - Christiane Werner
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
| | - Marco M Lehmann
- Swiss Federal Research Institute WSL, 8903 Birmensdorf, Switzerland
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3
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Dell'Acqua N, Gambetta GA, Delzon S, Ferrer N, Lamarque LJ, Saurin N, Theodore P, Delmas CEL. Mechanisms of grapevine resilience to a vascular disease: investigating stem radial growth, xylem development and physiological acclimation. Ann Bot 2024; 133:321-336. [PMID: 38066666 DOI: 10.1093/aob/mcad188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/07/2023] [Indexed: 04/11/2024]
Abstract
BACKGROUND AND AIMS Plant vascular diseases significantly impact crop yield worldwide. Esca is a vascular disease of grapevine found globally in vineyards which causes a loss of hydraulic conductance due to the occlusion of xylem vessels by tyloses. However, the integrated response of plant radial growth and physiology in maintaining xylem integrity in grapevine expressing esca symptoms remains poorly understood. METHODS We investigated the interplay between variation in stem diameter, xylem anatomy, plant physiological response and hydraulic traits in two widespread esca-susceptible cultivars, 'Sauvignon blanc' and 'Cabernet Sauvignon'. We used an original experimental design using naturally infected mature vines which were uprooted and transplanted into pots allowing for their study in a mini-lysimeter glasshouse phenotyping platform. KEY RESULTS Esca significantly altered the timing and sequence of stem growth periods in both cultivars, particularly the shrinkage phase following radial expansion. Symptomatic plants had a significantly higher density of occluded vessels and lower leaf and whole-plant gas exchange. Esca-symptomatic vines showed compensation mechanisms, producing numerous small functional xylem vessels later in development suggesting a maintenance of stem vascular cambium activity. Stabilization or late recovery of whole-plant stomatal conductance coincided with new healthy shoots at the top of the plant after esca symptoms plateaued. CONCLUSIONS Modified cropping practices, such as avoiding late-season topping, may enhance resilience in esca-symptomatic plants. These results highlight that integrating dendrometers, xylem anatomy and gas exchange provides insights into vascular pathogenesis and its effects on plant physiology.
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Affiliation(s)
- Ninon Dell'Acqua
- INRAE, Bordeaux Sciences Agro, ISVV, SAVE, F-33140, Villenave d'Ornon, France
| | - Gregory A Gambetta
- EGFV, Bordeaux-Sciences Agro, INRAE, Université de Bordeaux, ISVV, 210 chemin de Leysotte, 33882 Villenave d'Ornon, France
| | | | - Nathalie Ferrer
- INRAE, Bordeaux Sciences Agro, ISVV, SAVE, F-33140, Villenave d'Ornon, France
| | - Laurent J Lamarque
- Univ. Bordeaux, INRAE, BIOGECO, 33615 Pessac, France
- Département des Sciences de l'Environnement, Université du Québec à Trois-Rivières, Trois-Rivières, Canada
| | - Nicolas Saurin
- UE Pech Rouge, Univ Montpellier, INRAE, Gruissan, France
| | - Pauline Theodore
- INRAE, Bordeaux Sciences Agro, ISVV, SAVE, F-33140, Villenave d'Ornon, France
| | - Chloé E L Delmas
- INRAE, Bordeaux Sciences Agro, ISVV, SAVE, F-33140, Villenave d'Ornon, France
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4
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Buonaiuto DM, Davies TJ, Collins SC, Wolkovich EM. Ecological drivers of flower-leaf sequences: aridity and proxies for pollinator attraction select for flowering-first in the American plums. New Phytol 2024. [PMID: 38561636 DOI: 10.1111/nph.19685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/01/2024] [Indexed: 04/04/2024]
Abstract
Across temperate forests, many tree species produce flowers before their leaves emerge. This flower-leaf phenological sequence, known as hysteranthy, is generally described as an adaptation for wind pollination. However, this explanation does not address why hysteranthy is also common in biotically pollinated taxa. We quantified flower-leaf sequence variation in the American plums (Prunus, subg. Prunus sect. Prunocerasus), a clade of insect-pollinated trees, using herbaria specimens and Bayesian hierarchical modeling. We tested two common, but rarely interrogated hypotheses - that hysteranthy confers aridity tolerance and/or pollinator visibility - by modeling the associations between hysteranthy and related traits. To understand how these phenology-trait associations were sensitive to taxonomic scale and flower-leaf sequence classification, we then extended these analyses to all Prunus species in North America. Our findings across two taxonomic levels support the hypotheses that hysteranthy may help temporally partition hydraulic demand to reduce water stress and increase pollinator visibility - thereby reducing selective pressure on inflorescence size. Our results provide foundational insights into the evolution of flower-leaf sequences in the genus Prunus, with implications for understanding these patterns in biotically pollinated plants in general. Our approach suggests a path to advance these hypotheses to other clades, but teasing out drivers fully will require new experiments.
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Affiliation(s)
- D M Buonaiuto
- Department of Environmental Conservation, University of Massachusetts, Amherst, MA, 01003, USA
- Arnold Arboretum of Harvard University, Boston, MA, 02131, USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - T J Davies
- Forest & Conservation Sciences, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - S C Collins
- Forest & Conservation Sciences, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - E M Wolkovich
- Arnold Arboretum of Harvard University, Boston, MA, 02131, USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- Forest & Conservation Sciences, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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5
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Torres-Ruiz JM, Cochard H, Delzon S, Boivin T, Burlett R, Cailleret M, Corso D, Delmas CEL, De Caceres M, Diaz-Espejo A, Fernández-Conradi P, Guillemot J, Lamarque LJ, Limousin JM, Mantova M, Mencuccini M, Morin X, Pimont F, De Dios VR, Ruffault J, Trueba S, Martin-StPaul NK. Plant hydraulics at the heart of plant, crops and ecosystem functions in the face of climate change. New Phytol 2024; 241:984-999. [PMID: 38098153 DOI: 10.1111/nph.19463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 11/05/2023] [Indexed: 01/12/2024]
Abstract
Plant hydraulics is crucial for assessing the plants' capacity to extract and transport water from the soil up to their aerial organs. Along with their capacity to exchange water between plant compartments and regulate evaporation, hydraulic properties determine plant water relations, water status and susceptibility to pathogen attacks. Consequently, any variation in the hydraulic characteristics of plants is likely to significantly impact various mechanisms and processes related to plant growth, survival and production, as well as the risk of biotic attacks and forest fire behaviour. However, the integration of hydraulic traits into disciplines such as plant pathology, entomology, fire ecology or agriculture can be significantly improved. This review examines how plant hydraulics can provide new insights into our understanding of these processes, including modelling processes of vegetation dynamics, illuminating numerous perspectives for assessing the consequences of climate change on forest and agronomic systems, and addressing unanswered questions across multiple areas of knowledge.
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Affiliation(s)
- José M Torres-Ruiz
- Université Clermont-Auvergne, INRAE, PIAF, 63000, Clermont-Ferrand, France
| | - Hervé Cochard
- Université Clermont-Auvergne, INRAE, PIAF, 63000, Clermont-Ferrand, France
| | - Sylvain Delzon
- University of Bordeaux, INRAE, UMR BIOGECO, Pessac, 33615, France
| | | | - Regis Burlett
- University of Bordeaux, INRAE, UMR BIOGECO, Pessac, 33615, France
| | - Maxime Cailleret
- INRAE, Aix-Marseille Université, UMR RECOVER, Aix-en-Provence, 13100, France
| | - Déborah Corso
- University of Bordeaux, INRAE, UMR BIOGECO, Pessac, 33615, France
| | - Chloé E L Delmas
- INRAE, Bordeaux Sciences Agro, ISVV, SAVE, F-33140, Villenave d'Ornon, France
| | | | - Antonio Diaz-Espejo
- Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Seville, 41012, Spain
| | | | - Joannes Guillemot
- CIRAD, UMR Eco&Sols, Montpellier, 34394, France
- Eco&Sols, Univ. Montpellier, CIRAD, INRAe, Institut Agro, IRD, Montpellier, 34394, France
- Department of Forest Sciences, ESALQ, University of São Paulo, Piracicaba, 05508-060, São Paulo, Brazil
| | - Laurent J Lamarque
- Département des sciences de l'environnement, Université du Québec à Trois-Rivières, Trois-Rivières, G9A 5H7, Québec, Canada
| | | | - Marylou Mantova
- Agronomy Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - Maurizio Mencuccini
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, E08193, Spain
- ICREA, Barcelona, 08010, Spain
| | - Xavier Morin
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, 34394, France
| | | | - Victor Resco De Dios
- Department of Forest and Agricultural Science and Engineering, University of Lleida, Lleida, 25198, Spain
- JRU CTFC-AGROTECNIO-CERCA Center, Lleida, 25198, Spain
| | | | - Santiago Trueba
- University of Bordeaux, INRAE, UMR BIOGECO, Pessac, 33615, France
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6
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Paschalis A, De Kauwe MG, Sabot M, Fatichi S. When do plant hydraulics matter in terrestrial biosphere modelling? Glob Chang Biol 2024; 30:e17022. [PMID: 37962234 PMCID: PMC10952296 DOI: 10.1111/gcb.17022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023]
Abstract
The ascent of water from the soil to the leaves of vascular plants, described by the study of plant hydraulics, regulates ecosystem responses to environmental forcing and recovery from stress periods. Several approaches to model plant hydraulics have been proposed. In this study, we introduce four different versions of plant hydraulics representations in the terrestrial biosphere model T&C to understand the significance of plant hydraulics to ecosystem functioning. We tested representations of plant hydraulics, investigating plant water capacitance, and long-term xylem damages following drought. The four models we tested were a combination of representations including or neglecting capacitance and including or neglecting xylem damage legacies. Using the models at six case studies spanning semiarid to tropical ecosystems, we quantify how plant xylem flow, plant water storage and long-term xylem damage can modulate overall water and carbon dynamics across multiple time scales. We show that as drought develops, models with plant hydraulics predict a slower onset of plant water stress, and a diurnal variability of water and carbon fluxes closer to observations. Plant water storage was found to be particularly important for the diurnal dynamics of water and carbon fluxes, with models that include plant water capacitance yielding better results. Models including permanent damage to conducting plant tissues show an additional significant drought legacy effect, limiting plant productivity during the recovery phase following major droughts. However, when considering ecosystem responses to the observed climate variability, plant hydraulic modules alone cannot significantly improve the overall model performance, even though they reproduce more realistic water and carbon dynamics. This opens new avenues for model development, explicitly linking plant hydraulics with additional ecosystem processes, such as plant phenology and improved carbon allocation algorithms.
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Affiliation(s)
- Athanasios Paschalis
- Department of Civil and Environmental EngineeringImperial College LondonLondonUK
| | | | - Manon Sabot
- ARC Centre of Excellence for Climate Extremes and Climate Change Research CentreUniversity of New South WalesSydneyNew South WalesAustralia
| | - Simone Fatichi
- Department of Civil and Environmental EngineeringNational University of SingaporeSingaporeSingapore
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7
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Charra-Vaskou K, Lintunen A, Améglio T, Badel E, Cochard H, Mayr S, Salmon Y, Suhonen H, van Rooij M, Charrier G. Xylem embolism and bubble formation during freezing suggest complex dynamics of pressure in Betula pendula stems. J Exp Bot 2023; 74:5840-5853. [PMID: 37463327 DOI: 10.1093/jxb/erad275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 07/17/2023] [Indexed: 07/20/2023]
Abstract
Freeze-thaw-induced embolism, a key limiting factor for perennial plants results from the formation of gas bubbles during freezing and their expansion during thawing. However, the ice volumetric increase generates local pressures, which can affect the formation of bubbles. To characterize local dynamics of pressure tension and the physical state of the sap during freeze-thaw cycles, we simultaneously used ultrasonic acoustic emission analysis and synchrotron-based high-resolution computed tomography on the diffuse-porous species Betula pendula. Visualization of individual air-filled vessels and the distribution of gas bubbles in frozen xylem were performed.. Ultrasonic emissions occurred after ice formation, together with bubble formation, whereas the development of embolism took place after thawing. The pictures of frozen tissues indicated that the positive pressure induced by the volumetric increase of ice can provoke inward flow from the cell wall toward the lumen of the vessels. We found no evidence that wider vessels within a tissue were more prone to embolism, although the occurrence of gas bubbles in larger conduits would make them prone to earlier embolism. These results highlight the need to monitor local pressure as well as ice and air distribution during xylem freezing to understand the mechanism leading to frost-induced embolism.
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Affiliation(s)
| | - Anna Lintunen
- Institute for Atmospheric and Earth System Research/ Physics, Faculty of Science, University of Helsinki, Finland
- Institute for Atmospheric and Earth System Research/ Forest Science, Faculty of Agriculture and Forestry, University of Helsinki, Finland
| | - Thierry Améglio
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Eric Badel
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Hervé Cochard
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Stefan Mayr
- Institute for Botany, University of Innsbruck, Austria
| | - Yann Salmon
- Institute for Atmospheric and Earth System Research/ Physics, Faculty of Science, University of Helsinki, Finland
- Institute for Atmospheric and Earth System Research/ Forest Science, Faculty of Agriculture and Forestry, University of Helsinki, Finland
| | | | - Mahaut van Rooij
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Guillaume Charrier
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
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8
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Schönbeck L, Arteaga M, Mirza H, Coleman M, Mitchell D, Huang X, Ortiz H, Santiago LS. Plant physiological indicators for optimizing conservation outcomes. Conserv Physiol 2023; 11:coad073. [PMID: 37711583 PMCID: PMC10498484 DOI: 10.1093/conphys/coad073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 07/20/2023] [Accepted: 08/22/2023] [Indexed: 09/16/2023]
Abstract
Plant species of concern often occupy narrow habitat ranges, making climate change an outsized potential threat to their conservation and restoration. Understanding the physiological status of a species during stress has the potential to elucidate current risk and provide an outlook on population maintenance. However, the physiological status of a plant can be difficult to interpret without a reference point, such as the capacity to tolerate stress before loss of function, or mortality. We address the application of plant physiology to conservation biology by distinguishing between two physiological approaches that together determine plant status in relation to environmental conditions and evaluate the capacity to avoid stress-induced loss of function. Plant physiological status indices, such as instantaneous rates of photosynthetic gas exchange, describe the level of physiological activity in the plant and are indicative of physiological health. When such measurements are combined with a reference point that reflects the maximum value or environmental limits of a parameter, such as the temperature at which photosynthesis begins to decline due to high temperature stress, we can better diagnose the proximity to potentially damaging thresholds. Here, we review a collection of useful plant status and reference point measurements related to photosynthesis, water relations and mineral nutrition, which can contribute to plant conservation physiology. We propose that these measurements can serve as important additional information to more commonly used phenological and morphological parameters, as the proposed parameters will reveal early warning signals before they are visible. We discuss their implications in the context of changing temperature, water and nutrient supply.
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Affiliation(s)
- Leonie Schönbeck
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Marc Arteaga
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Humera Mirza
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Mitchell Coleman
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
- Tejon Ranch Conservancy, Frazier Park, CA 93225, USA
| | - Denise Mitchell
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Xinyi Huang
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Haile Ortiz
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Louis S Santiago
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
- Smithsonian Tropical Research Institute, Apartado 0843-03092. Balboa, Ancon, Panama, Republic of Panama
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9
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Ding J, McDowell N, Fang Y, Ward N, Kirwan ML, Regier P, Megonigal P, Zhang P, Zhang H, Wang W, Li W, Pennington SC, Wilson SJ, Stearns A, Bailey V. Modeling the mechanisms of conifer mortality under seawater exposure. New Phytol 2023. [PMID: 37376720 DOI: 10.1111/nph.19076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023]
Abstract
Relative sea level rise (SLR) increasingly impacts coastal ecosystems through the formation of ghost forests. To predict the future of coastal ecosystems under SLR and changing climate, it is important to understand the physiological mechanisms underlying coastal tree mortality and to integrate this knowledge into dynamic vegetation models. We incorporate the physiological effect of salinity and hypoxia in a dynamic vegetation model in the Earth system land model, and used the model to investigate the mechanisms of mortality of conifer forests on the west and east coast sites of USA, where trees experience different form of sea water exposure. Simulations suggest similar physiological mechanisms can result in different mortality patterns. At the east coast site that experienced severe increases in seawater exposure, trees loose photosynthetic capacity and roots rapidly, and both storage carbon and hydraulic conductance decrease significantly within a year. Over time, further consumption of storage carbon that leads to carbon starvation dominates mortality. At the west coast site that gradually exposed to seawater through SLR, hydraulic failure dominates mortality because root loss impacts on conductance are greater than the degree of storage carbon depletion. Measurements and modeling focused on understanding the physiological mechanisms of mortality is critical to reducing predictive uncertainty.
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Affiliation(s)
- Junyan Ding
- Biological Sciences Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
| | - Nate McDowell
- Biological Sciences Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA, 99164-4236, USA
| | - Yilin Fang
- Earth Systems Science Division, Pacific Northwest National Lab, Richland, WA, 99352, USA
| | - Nicholas Ward
- Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory, Sequim, WA, 98382, USA
| | - Matthew L Kirwan
- Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA, 23062, USA
| | - Peter Regier
- Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory, Sequim, WA, 98382, USA
| | - Patrick Megonigal
- Smithsonian Environmental Research Center, Edgewater, MD, 21037, USA
| | - Peipei Zhang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Hongxia Zhang
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Wenzhi Wang
- The Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Weibin Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China
| | - Stephanie C Pennington
- Joint Global Change Research Institute, Pacific Northwest National Laboratory, College Park, MD, 20740, USA
| | | | - Alice Stearns
- Smithsonian Environmental Research Center, Edgewater, MD, 21037, USA
| | - Vanessa Bailey
- Biological Sciences Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
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10
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Wilkening JV, Skelton RP, Feng X, Dawson TE, Thompson SE. Exploring within-plant hydraulic trait variation: A test of the vulnerability segmentation hypothesis. Plant Cell Environ 2023. [PMID: 37338073 DOI: 10.1111/pce.14649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 05/30/2023] [Accepted: 06/04/2023] [Indexed: 06/21/2023]
Abstract
Observations show vulnerability segmentation between stems and leaves is highly variable within and between environments. While a number of species exhibit conventional vulnerability segmentation (stem P 50 < ${P}_{50}\lt $ leaf P 50 ${P}_{50}$ ), others exhibit no vulnerability segmentation and others reverse vulnerability segmentation (stem P 50 > ${P}_{50}\gt $ leaf P 50 ${P}_{50}$ ). We developed a hydraulic model to test hypotheses about vulnerability segmentation and how it interacts with other traits to impact plant conductance. We do this using a series of experiments across a broad parameter space and with a case study of two species with contrasting vulnerability segmentation patterns: Quercus douglasii and Populus trichocarpa. We found that while conventional vulnerability segmentation helps to preserve conductance in stem tissues, reverse vulnerability segmentation can better maintain conductance across the combined stem-leaf hydraulic pathway, particularly when plants have more vulnerable P 50 ${P}_{50}$ s and have hydraulic segmentation with greater resistance in the leaves. These findings show that the impacts of vulnerability segmentation are dependent upon other plant traits, notably hydraulic segmentation, a finding that could assist in the interpretation of variable observations of vulnerability segmentation. Further study is needed to examine how vulnerability segmentation impacts transpiration rates and recovery from water stress.
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Affiliation(s)
- Jean V Wilkening
- Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California, USA
- Civil, Environmental, and Geo- Engineering, University of Minnesota, Minneapolis, Minnesota, USA
- St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, Minnesota, USA
| | - Robert P Skelton
- South African Environmental Observation Network, Cape Town, South Africa
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Xue Feng
- Civil, Environmental, and Geo- Engineering, University of Minnesota, Minneapolis, Minnesota, USA
- St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, Minnesota, USA
| | - Todd E Dawson
- Integrative Biology, University of California, Berkeley, Berkeley, California, USA
| | - Sally E Thompson
- Civil, Environmental, and Mining Engineering, University of Western Australia, Perth, Western Australia, Australia
- Centre for Water and Spatial Science, University of Western Australia, Perth, Western Australia, Australia
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11
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Rowland L, Ramírez-Valiente JA, Hartley IP, Mencuccini M. How woody plants adjust above- and below-ground traits in response to sustained drought. New Phytol 2023. [PMID: 37306017 DOI: 10.1111/nph.19000] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 04/01/2023] [Indexed: 06/13/2023]
Abstract
Future increases in drought severity and frequency are predicted to have substantial impacts on plant function and survival. However, there is considerable uncertainty concerning what drought adjustment is and whether plants can adjust to sustained drought. This review focuses on woody plants and synthesises the evidence for drought adjustment in a selection of key above-ground and below-ground plant traits. We assess whether evaluating the drought adjustment of single traits, or selections of traits that operate on the same plant functional axis (e.g. photosynthetic traits) is sufficient, or whether a multi-trait approach, integrating across multiple axes, is required. We conclude that studies on drought adjustments in woody plants might overestimate the capacity for adjustment to drier environments if spatial studies along gradients are used, without complementary experimental approaches. We provide evidence that drought adjustment is common in above-ground and below-ground traits; however, whether this is adaptive and sufficient to respond to future droughts remains uncertain for most species. To address this uncertainty, we must move towards studying trait integration within and across multiple axes of plant function (e.g. above-ground and below-ground) to gain a holistic view of drought adjustments at the whole-plant scale and how these influence plant survival.
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Affiliation(s)
- Lucy Rowland
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RJ, UK
| | | | - Iain P Hartley
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RJ, UK
| | - Maurizio Mencuccini
- CREAF, Campus de Bellaterra (UAB), Cerdanyola del Vallés, Barcelona, 08193, Spain
- ICREA, Barcelona, 08010, Spain
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12
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Jin Y, Hao G, Hammond WM, Yu K, Liu X, Ye Q, Zhou Z, Wang C. Aridity-dependent sequence of water potentials for stomatal closure and hydraulic dysfunctions in woody plants. Glob Chang Biol 2023; 29:2030-2040. [PMID: 36655297 DOI: 10.1111/gcb.16605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/01/2023] [Indexed: 05/28/2023]
Abstract
The sequence of physiological events during drought strongly impacts plants' overall performance. Here, we synthesized the global data of stomatal and hydraulic traits in leaves and stems of 202 woody species to evaluate variations in the water potentials for key physiological events and their sequence along the climatic gradient. We found that the seasonal minimum water potential, turgor loss point, stomatal closure point, and leaf and stem xylem vulnerability to embolism were intercorrelated and decreased with aridity, indicating that water stress drives trait co-selection. In xeric regions, the seasonal minimum water potential occurred at lower water potential than turgor loss point, and the subsequent stomatal closure delayed embolism formation. In mesic regions, however, the seasonal minimum water potential did not pose a threat to the physiological functions, and stomatal closure occurred even at slightly more negative water potential than embolism. Our study demonstrates that the sequence of water potentials for physiological dysfunctions of woody plants varies with aridity, that is, xeric species adopt a more conservative sequence to prevent severe tissue damage through tighter stomatal regulation (isohydric strategy) and higher embolism resistance, while mesic species adopt a riskier sequence via looser stomatal regulation (anisohydric strategy) to maximize carbon uptake at the cost of hydraulic safety. Integrating both aridity-dependent sequence of water potentials for physiological dysfunctions and gap between these key traits into the hydraulic framework of process-based vegetation models would improve the prediction of woody plants' responses to drought under global climate change.
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Affiliation(s)
- Ying Jin
- Key Laboratory of Sustainable Forest Ecosystem Management, Center for Ecological Research, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Guangyou Hao
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - William M Hammond
- Agronomy Department, University of Florida, Gainesville, Florida, USA
| | - Kailiang Yu
- Department of Ecology & Evolutionary Biology, High Meadows Environmental Institute, Princeton University, Princeton, New Jersey, USA
| | - Xiaorong Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Zhenghu Zhou
- Key Laboratory of Sustainable Forest Ecosystem Management, Center for Ecological Research, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Chuankuan Wang
- Key Laboratory of Sustainable Forest Ecosystem Management, Center for Ecological Research, Ministry of Education, Northeast Forestry University, Harbin, China
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13
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Buckley TN, Frehner EH, Bailey BN. Kinetic factors of physiology and the dynamic light environment influence the economic landscape of short-term hydraulic risk. New Phytol 2023; 238:529-548. [PMID: 36650668 DOI: 10.1111/nph.18739] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
Optimality-based models of stomatal conductance unify biophysical and evolutionary constraints and can improve predictions of land-atmosphere carbon and water exchange. Recent models incorporate hydraulic constraints by penalizing excessive stomatal opening in relation to hydraulic damage caused by low water potentials. We used simulation models to test whether penalties based solely on vulnerability curves adequately represent the optimality hypothesis, given that they exclude the effects of kinetic factors on stomatal behavior and integrated carbon balance. To quantify the effects of nonsteady-state phenomena on the landscape of short-term hydraulic risk, we simulated diurnal dynamics of leaf physiology for 10 000 patches of leaf in a canopy and used a ray-tracing model, Helios, to simulate realistic variation in sunfleck dynamics. Our simulations demonstrated that kinetic parameters of leaf physiology and sunfleck properties influence the economic landscape of short-term hydraulic risk, as characterized by the effect of stomatal strategy (gauged by the water potential causing a 50% hydraulic penalty) on both aggregated carbon gain and the aggregated carbon cost of short-term hydraulic risk. Hydraulic penalties in optimization models should be generalized to allow their parameters to account for kinetic factors, in addition to parameters of hydraulic vulnerability.
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Affiliation(s)
- Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, Davis, CA, 95616, USA
| | - Ethan H Frehner
- Department of Plant Sciences, University of California, Davis, Davis, CA, 95616, USA
| | - Brian N Bailey
- Department of Plant Sciences, University of California, Davis, Davis, CA, 95616, USA
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14
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Wolfe BT, Detto M, Zhang YJ, Anderson-Teixeira KJ, Brodribb T, Collins AD, Crawford C, Dickman LT, Ely KS, Francisco J, Gurry PD, Hancock H, King CT, Majekobaje AR, Mallett CJ, McDowell NG, Mendheim Z, Michaletz ST, Myers DB, Price TJ, Rogers A, Sack L, Serbin SP, Siddiq Z, Willis D, Wu J, Zailaa J, Wright SJ. Leaves as bottlenecks: The contribution of tree leaves to hydraulic resistance within the soil-plant-atmosphere continuum. Plant Cell Environ 2023; 46:736-746. [PMID: 36564901 DOI: 10.1111/pce.14524] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/12/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Within vascular plants, the partitioning of hydraulic resistance along the soil-to-leaf continuum affects transpiration and its response to environmental conditions. In trees, the fractional contribution of leaf hydraulic resistance (Rleaf ) to total soil-to-leaf hydraulic resistance (Rtotal ), or fRleaf (=Rleaf /Rtotal ), is thought to be large, but this has not been tested comprehensively. We compiled a multibiome data set of fRleaf using new and previously published measurements of pressure differences within trees in situ. Across 80 samples, fRleaf averaged 0.51 (95% confidence interval [CI] = 0.46-0.57) and it declined with tree height. We also used the allometric relationship between field-based measurements of soil-to-leaf hydraulic conductance and laboratory-based measurements of leaf hydraulic conductance to compute the average fRleaf for 19 tree samples, which was 0.40 (95% CI = 0.29-0.56). The in situ technique produces a more accurate descriptor of fRleaf because it accounts for dynamic leaf hydraulic conductance. Both approaches demonstrate the outsized role of leaves in controlling tree hydrodynamics. A larger fRleaf may help stems from loss of hydraulic conductance. Thus, the decline in fRleaf with tree height would contribute to greater drought vulnerability in taller trees and potentially to their observed disproportionate drought mortality.
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Affiliation(s)
- Brett T Wolfe
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
| | - Matteo Detto
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, Maine, USA
| | - Kristina J Anderson-Teixeira
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, Virginia, USA
| | - Tim Brodribb
- School of Natural Sciences, University of Tasmania, Hobart, Australia
| | - Adam D Collins
- Los Alamos National Laboratory, Earth and Environmental Sciences Division, Los Alamos, New Mexico, USA
| | - Chloe Crawford
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - L Turin Dickman
- Los Alamos National Laboratory, Earth and Environmental Sciences Division, Los Alamos, New Mexico, USA
| | - Kim S Ely
- Brookhaven National Laboratory, Environmental and Climate Science Department, Upton, New York, USA
| | - Jessica Francisco
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Preston D Gurry
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Haigan Hancock
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Christopher T King
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Adelodun R Majekobaje
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Christian J Mallett
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Nate G McDowell
- Pacific Northwest National Lab, Atmospheric Sciences and Global Change Division, Richland, Washington, USA
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Zachary Mendheim
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Sean T Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Daniel B Myers
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Ty J Price
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Alistair Rogers
- Brookhaven National Laboratory, Environmental and Climate Science Department, Upton, New York, USA
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
| | - Shawn P Serbin
- Brookhaven National Laboratory, Environmental and Climate Science Department, Upton, New York, USA
| | - Zafar Siddiq
- Department of Botany, Government College University, Lahore, Pakistan
| | - David Willis
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Jin Wu
- School of Biological Sciences, Research Area of Ecology and Biodiversity, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Joseph Zailaa
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, Virginia, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
- School of the Environment, Yale University, New Haven, Connecticut, USA
| | - S Joseph Wright
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
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15
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Ruffault J, Limousin JM, Pimont F, Dupuy JL, De Càceres M, Cochard H, Mouillot F, Blackman CJ, Torres-Ruiz JM, Parsons RA, Moreno M, Delzon S, Jansen S, Olioso A, Choat B, Martin-StPaul N. Plant hydraulic modelling of leaf and canopy fuel moisture content reveals increasing vulnerability of a Mediterranean forest to wildfires under extreme drought. New Phytol 2023; 237:1256-1269. [PMID: 36366950 DOI: 10.1111/nph.18614] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Fuel moisture content (FMC) is a crucial driver of forest fires in many regions world-wide. Yet, the dynamics of FMC in forest canopies as well as their physiological and environmental determinants remain poorly understood, especially under extreme drought. We embedded a FMC module in the trait-based, plant-hydraulic SurEau-Ecos model to provide innovative process-based predictions of leaf live fuel moisture content (LFMC) and canopy fuel moisture content (CFMC) based on leaf water potential ( ψ Leaf ). SurEau-Ecos-FMC relies on pressure-volume (p-v) curves to simulate LFMC and vulnerability curves to cavitation to simulate foliage mortality. SurEau-Ecos-FMC accurately reproduced ψ Leaf and LFMC dynamics as well as the occurrence of foliage mortality in a Mediterranean Quercus ilex forest. Several traits related to water use (leaf area index, available soil water, and transpiration regulation), vulnerability to cavitation, and p-v curves (full turgor osmotic potential) had the greatest influence on LFMC and CFMC dynamics. As the climate gets drier, our results showed that drought-induced foliage mortality is expected to increase, thereby significantly decreasing CFMC. Our results represent an important advance in our capacity to understand and predict the sensitivity of forests to wildfires.
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Affiliation(s)
| | | | | | | | | | - Hervé Cochard
- Université Clermont-Auvergne, INRAE, PIAF, 63000, Clermont-Ferrand, France
| | - Florent Mouillot
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, 34000, Montpellier, France
| | - Chris J Blackman
- School of Biological Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
| | - José M Torres-Ruiz
- Université Clermont-Auvergne, INRAE, PIAF, 63000, Clermont-Ferrand, France
| | - Russell A Parsons
- Fire Sciences Laboratory, Rocky Mountain Research Station, USDA Forest Service, Missoula, MT, 59808, USA
| | | | | | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, D-89081, Ulm, Germany
| | | | - Brendan Choat
- Western Sydney University, Penrith, NSW, 2751, Australia
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16
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Li X, Xi B, Wu X, Choat B, Feng J, Jiang M, Tissue D. Corrigendum: Unlocking drought-induced tree mortality: Physiological mechanisms to modelling. Front Plant Sci 2023; 13:1126049. [PMID: 36699856 PMCID: PMC9869915 DOI: 10.3389/fpls.2022.1126049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
[This corrects the article DOI: 10.3389/fpls.2022.835921.].
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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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17
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Chen YJ, Maenpuen P, Zhang JL, Zhang YJ. Remaining uncertainties in the Pneumatic method. New Phytol 2023; 237:384-391. [PMID: 36537302 DOI: 10.1111/nph.18530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 10/01/2022] [Indexed: 06/17/2023]
Affiliation(s)
- Ya-Jun Chen
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
- Yuanjiang Savanna Ecosystem Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yuanjiang, Yunnan, 653300, China
| | - Phisamai Maenpuen
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiao-Lin Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA
- Climate Change Institute, University of Maine, Orono, ME, 04469, USA
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18
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Rockwell FE, Holbrook NM, Jain P, Huber AE, Sen S, Stroock AD. Extreme undersaturation in the intercellular airspace of leaves: a failure of Gaastra or Ohm? Ann Bot 2022; 130:301-316. [PMID: 35896037 PMCID: PMC9486918 DOI: 10.1093/aob/mcac094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 07/21/2022] [Indexed: 06/09/2023]
Abstract
BACKGROUND Recent reports of extreme levels of undersaturation in internal leaf air spaces have called into question one of the foundational assumptions of leaf gas exchange analysis, that leaf air spaces are effectively saturated with water vapour at leaf surface temperature. Historically, inferring the biophysical states controlling assimilation and transpiration from the fluxes directly measured by gas exchange systems has presented a number of challenges, including: (1) a mismatch in scales between the area of flux measurement, the biochemical cellular scale and the meso-scale introduced by the localization of the fluxes to stomatal pores; (2) the inaccessibility of the internal states of CO2 and water vapour required to define conductances; and (3) uncertainties about the pathways these internal fluxes travel. In response, plant physiologists have adopted a set of simplifying assumptions that define phenomenological concepts such as stomatal and mesophyll conductances. SCOPE Investigators have long been concerned that a failure of basic assumptions could be distorting our understanding of these phenomenological conductances, and the biophysical states inside leaves. Here we review these assumptions and historical efforts to test them. We then explore whether artefacts in analysis arising from the averaging of fluxes over macroscopic leaf areas could provide alternative explanations for some part, if not all, of reported extreme states of undersaturation. CONCLUSIONS Spatial heterogeneities can, in some cases, create the appearance of undersaturation in the internal air spaces of leaves. Further refinement of experimental approaches will be required to separate undersaturation from the effects of spatial variations in fluxes or conductances. Novel combinations of current and emerging technologies hold promise for meeting this challenge.
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Affiliation(s)
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Piyush Jain
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA
| | - Annika E Huber
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA
| | - Sabyasachi Sen
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA
| | - Abraham D Stroock
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA
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19
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Smith-Martin CM, Muscarella R, Ankori-Karlinsky R, Delzon S, Farrar SL, Salva-Sauri M, Thompson J, Zimmerman JK, Uriarte M. Hurricanes increase tropical forest vulnerability to drought. New Phytol 2022; 235:1005-1017. [PMID: 35608089 DOI: 10.1111/nph.18175] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 04/07/2022] [Indexed: 06/15/2023]
Abstract
Rapid changes in climate and disturbance regimes, including droughts and hurricanes, are likely to influence tropical forests, but our understanding of the compound effects of disturbances on forest ecosystems is extremely limited. Filling this knowledge gap is necessary to elucidate the future of these ecosystems under a changing climate. We examined the relationship between hurricane response (damage, mortality, and resilience) and four hydraulic traits of 13 dominant woody species in a wet tropical forest subject to periodic hurricanes. Species with high resistance to embolisms (low P50 values) and higher safety margins ( SMP50 ) were more resistant to immediate hurricane mortality and breakage, whereas species with higher hurricane resilience (rapid post-hurricane growth) had high capacitance and P50 values and low SMP50 . During 26 yr of post-hurricane recovery, we found a decrease in community-weighted mean values for traits associated with greater drought resistance (leaf turgor loss point, P50 , SMP50 ) and an increase in capacitance, which has been linked with lower drought resistance. Hurricane damage favors slow-growing, drought-tolerant species, whereas post-hurricane high resource conditions favor acquisitive, fast-growing but drought-vulnerable species, increasing forest productivity at the expense of drought tolerance and leading to higher overall forest vulnerability to drought.
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Affiliation(s)
- Chris M Smith-Martin
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA
| | - Robert Muscarella
- Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, 752 36, Sweden
| | - Roi Ankori-Karlinsky
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA
| | - Sylvain Delzon
- INRA, BIOGECO, Université Bordeaux, Pessac, 33615, France
| | - Samuel L Farrar
- Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, 752 36, Sweden
| | - Melissa Salva-Sauri
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA
- Department of Environmental Sciences, University of Puerto Rico, San Juan, PR, 00925, USA
| | - Jill Thompson
- UK Centre for Ecology & Hydrology Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
| | - Jess K Zimmerman
- Department of Environmental Sciences, University of Puerto Rico, San Juan, PR, 00925, USA
| | - María Uriarte
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA
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Knipfer T, Cuneo IF. Editorial: Plant-water relations for sustainable agriculture. Front Plant Sci 2022; 13:979804. [PMID: 35968136 PMCID: PMC9366731 DOI: 10.3389/fpls.2022.979804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Thorsten Knipfer
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Italo F. Cuneo
- Facuty of Agriculture and Food Science, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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21
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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. Glob Chang Biol 2022; 28:4359-4376. [PMID: 35373899 DOI: 10.1111/gcb.16179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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De Kauwe MG, Sabot MEB, Medlyn BE, Pitman AJ, Meir P, Cernusak LA, Gallagher RV, Ukkola AM, Rifai SW, Choat B. Towards species-level forecasts of drought-induced tree mortality risk. New Phytol 2022; 235:94-110. [PMID: 35363880 PMCID: PMC9321630 DOI: 10.1111/nph.18129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/28/2022] [Indexed: 05/14/2023]
Abstract
Predicting species-level responses to drought at the landscape scale is critical to reducing uncertainty in future terrestrial carbon and water cycle projections. We embedded a stomatal optimisation model in the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model and parameterised the model for 15 canopy dominant eucalypt tree species across South-Eastern Australia (mean annual precipitation range: 344-1424 mm yr-1 ). We conducted three experiments: applying CABLE to the 2017-2019 drought; a 20% drier drought; and a 20% drier drought with a doubling of atmospheric carbon dioxide (CO2 ). The severity of the drought was highlighted as for at least 25% of their distribution ranges, 60% of species experienced leaf water potentials beyond the water potential at which 50% of hydraulic conductivity is lost due to embolism. We identified areas of severe hydraulic stress within-species' ranges, but we also pinpointed resilience in species found in predominantly semiarid areas. The importance of the role of CO2 in ameliorating drought stress was consistent across species. Our results represent an important advance in our capacity to forecast the resilience of individual tree species, providing an evidence base for decision-making around the resilience of restoration plantings or net-zero emission strategies.
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Affiliation(s)
| | - Manon E. B. Sabot
- ARC Centre of Excellence for Climate ExtremesSydneyNSW2052Australia
- Climate Change Research CentreUniversity of New South WalesSydneyNSW2052Australia
| | - Belinda E. Medlyn
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
| | - Andrew J. Pitman
- ARC Centre of Excellence for Climate ExtremesSydneyNSW2052Australia
- Climate Change Research CentreUniversity of New South WalesSydneyNSW2052Australia
| | - Patrick Meir
- School of GeosciencesThe University of EdinburghEdinburghEH9 3FFUK
| | - Lucas A. Cernusak
- College of Science and EngineeringJames Cook UniversityCairnsQld4878Australia
| | - Rachael V. Gallagher
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
| | - Anna M. Ukkola
- ARC Centre of Excellence for Climate ExtremesSydneyNSW2052Australia
- Climate Change Research CentreUniversity of New South WalesSydneyNSW2052Australia
| | - Sami W. Rifai
- ARC Centre of Excellence for Climate ExtremesSydneyNSW2052Australia
- Climate Change Research CentreUniversity of New South WalesSydneyNSW2052Australia
| | - Brendan Choat
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
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Echeverría A, Petrone‐Mendoza E, Segovia‐Rivas A, Figueroa‐Abundiz VA, Olson ME. The vessel wall thickness-vessel diameter relationship across woody angiosperms. Am J Bot 2022; 109:856-873. [PMID: 35435252 PMCID: PMC9328290 DOI: 10.1002/ajb2.1854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 05/26/2023]
Abstract
PREMISE Comparative anatomy is necessary to identify the extremes of combinations of functionally relevant structural traits, to ensure that physiological data cover xylem anatomical diversity adequately, and thus achieve a global understanding of xylem structure-function relations. A key trait relationship is that between xylem vessel diameter and wall thickness of both the single vessel and the double vessel+adjacent imperforate tracheary element (ITE). METHODS We compiled a comparative data set with 1093 samples, 858 species, 350 genera, 86 families, and 33 orders. We used broken linear regression and an algorithm to explore changes in parameter values from linear regressions using subsets of the data set to identify a threshold, at 90-µm vessel diameter, in the wall thickness-diameter relationship. RESULTS Below 90 µm diameter for vessels, virtually any wall thickness could be associated with virtually any diameter. Below this threshold, selection is free to favor a very wide array of combinations, such as very thick walls and narrow vessels in ITE-free herbs, or very thin-walled, wide vessels in evergreen dryland pioneers. Above 90 µm, there was a moderate positive relationship. CONCLUSIONS Our analysis shows that the space of vessel wall thickness-diameter combinations is very wide, with selection apparently eliminating individuals with vessel walls "too thin" for their diameter. Most importantly, our survey revealed poorly studied plant hydraulic syndromes (functionally significant trait combinations). These data suggest that the full span of trait combinations, and thus the minimal set of hydraulic syndromes requiring study to span woody plant functional diversity adequately, remains to be documented.
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Affiliation(s)
- Alberto Echeverría
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México, 04510México
| | - Emilio Petrone‐Mendoza
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México, 04510México
| | - Alí Segovia‐Rivas
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México, 04510México
| | - Víctor A. Figueroa‐Abundiz
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México, 04510México
| | - Mark E. Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México, 04510México
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24
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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. Front Plant Sci 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] [What about the content of this article? (0)] [Affiliation(s)] [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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25
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Slater H, Dolan L. The New Phytologist Tansley Medal 2021 - Michał Bogdziewicz and Anna T. Trugman. New Phytol 2022; 234:5-6. [PMID: 35238046 DOI: 10.1111/nph.18033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
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26
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Trugman AT. Integrating plant physiology and community ecology across scales through trait-based models to predict drought mortality. New Phytol 2022; 234:21-27. [PMID: 34679225 DOI: 10.1111/nph.17821] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/02/2021] [Indexed: 06/13/2023]
Abstract
Forests are a critical carbon sink and widespread tree mortality resulting from climate-induced drought stress has the potential to alter forests from a carbon sink to a source, causing a positive feedback on climate change. Process-based vegetation models aim to represent the current understanding of the underlying mechanisms governing plant physiological and ecological responses to climate. Yet model accuracy varies across scales, and regional-scale model predictive skill is frequently poor when compared with observations of drought-driven mortality. I propose a framework that leverages differences in model predictive skill across spatial scales, mismatches between model predictions and observations, and differences in the mechanisms included and absent across models to advance the understanding of the physiological and ecological processes driving observed patterns drought-driven mortality.
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Affiliation(s)
- Anna T Trugman
- Department of Geography, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
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27
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28
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Bok ECPM, Brodribb TJ, Jordan GJ, Carriquí M. Convergent tip-to-base widening of water-conducting conduits in the tallest bryophytes. Am J Bot 2022; 109:322-332. [PMID: 34713894 DOI: 10.1002/ajb2.1795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/02/2021] [Accepted: 10/26/2021] [Indexed: 06/13/2023]
Abstract
PREMISE Tip-to-base conduit widening is considered a key mechanism that enables vascular plants to grow tall by decreasing the hydraulic resistance imposed by increasing height. Widening of hydraulic anatomy (larger conducting elements toward the base of the vascular system) minimizes gradients in leaf-specific hydraulic conductance with plant height, allowing uniform photosynthesis across the crown of trees. Tip-to-base conduit widening has also been associated with changes in conduit number. However, in bryophytes, despite having representatives with internal water-conducting tissue, conduit widening has been scarcely investigated. METHODS Here, we examined the changes in hydroid diameter and number with distance from plant tip in Dawsonia superba and D. polytrichoides, two representatives of the genus containing the tallest extant bryophytes. RESULTS The position of these moss species on the global scale of conduit size and plant size was consistent with a general scaling among plants with internal water transport. Within plants, patterns of conduit widening and number with distance from plant tip in endohydric mosses were similar to those observed in vascular plants. CONCLUSIONS This study demonstrated that land plants growing upward in the atmosphere show analogous conduit widening of hydraulic structures, suggesting that efficient internal water transport is a convergent adaptation for photosynthesis on land.
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Affiliation(s)
- Erin C P M Bok
- Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Timothy J Brodribb
- Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Gregory J Jordan
- Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Marc Carriquí
- Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
- Department of Biology, University of the Balearic Islands, Palma, Illes Balears, Spain
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29
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Pivovaroff AL, McDowell NG, Rodrigues TB, Brodribb T, Cernusak LA, Choat B, Grossiord C, Ishida Y, Jardine KJ, Laurance S, Leff R, Li W, Liddell M, Mackay DS, Pacheco H, Peters J, de J Sampaio Filho I, Souza DC, Wang W, Zhang P, Chambers J. Stability of tropical forest tree carbon-water relations in a rainfall exclusion treatment through shifts in effective water uptake depth. Glob Chang Biol 2021; 27:6454-6466. [PMID: 34469040 DOI: 10.1111/gcb.15869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
Increasing severity and frequency of drought is predicted for large portions of the terrestrial biosphere, with major impacts already documented in wet tropical forests. Using a 4-year rainfall exclusion experiment in the Daintree Rainforest in northeast Australia, we examined canopy tree responses to reduced precipitation and soil water availability by quantifying seasonal changes in plant hydraulic and carbon traits for 11 tree species between control and drought treatments. Even with reduced soil volumetric water content in the upper 1 m of soil in the drought treatment, we found no significant difference between treatments for predawn and midday leaf water potential, photosynthesis, stomatal conductance, foliar stable carbon isotope composition, leaf mass per area, turgor loss point, xylem vessel anatomy, or leaf and stem nonstructural carbohydrates. While empirical measurements of aboveground traits revealed homeostatic maintenance of plant water status and traits in response to reduced soil moisture, modeled belowground dynamics revealed that trees in the drought treatment shifted the depth from which water was acquired to deeper soil layers. These findings reveal that belowground acclimation of tree water uptake depth may buffer tropical rainforests from more severe droughts that may arise in future with climate change.
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Affiliation(s)
- Alexandria L Pivovaroff
- Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Nate G McDowell
- Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington, USA
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Tayana Barrozo Rodrigues
- Forest Management Laboratory, National Institute of Amazonian Research, Manaus, Amazonas, Brazil
| | - Tim Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Brendan Choat
- University of Western Sydney, Hawkesbury Institute for the Environment, Richmond, New South Wales, Australia
| | - Charlotte Grossiord
- Plant Ecology Research Laboratory, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, Switzerland
- Functional Plant Ecology, Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Lausanne, Switzerland
| | - Yoko Ishida
- College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Kolby J Jardine
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Susan Laurance
- College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Riley Leff
- Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Weibin Li
- Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington, USA
- State Key Laboratory of Grassland and Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Michael Liddell
- College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - D Scott Mackay
- Department of Geography and Department of Environment & Sustainability, University at Buffalo, Buffalo, New York, USA
| | - Heather Pacheco
- Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Jennifer Peters
- University of Western Sydney, Hawkesbury Institute for the Environment, Richmond, New South Wales, Australia
- Oak Ridge National Laboratory, Climate Change Science Institute & Environmental Science Division, Oak Ridge, Tennessee, USA
| | | | - Daisy C Souza
- Forest Management Laboratory, National Institute of Amazonian Research, Manaus, Amazonas, Brazil
| | - Wenzhi Wang
- Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Peipei Zhang
- Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Jeff Chambers
- Climate Sciences Department, Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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30
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Xu H, Wang H, Prentice IC, Harrison SP, Wright IJ. Coordination of plant hydraulic and photosynthetic traits: confronting optimality theory with field measurements. New Phytol 2021; 232:1286-1296. [PMID: 34324717 PMCID: PMC9291854 DOI: 10.1111/nph.17656] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 07/26/2021] [Indexed: 05/13/2023]
Abstract
Close coupling between water loss and carbon dioxide uptake requires coordination of plant hydraulics and photosynthesis. However, there is still limited information on the quantitative relationships between hydraulic and photosynthetic traits. We propose a basis for these relationships based on optimality theory, and test its predictions by analysis of measurements on 107 species from 11 sites, distributed along a nearly 3000-m elevation gradient. Hydraulic and leaf economic traits were less plastic, and more closely associated with phylogeny, than photosynthetic traits. The two sets of traits were linked by the sapwood to leaf area ratio (Huber value, vH ). The observed coordination between vH and sapwood hydraulic conductivity (KS ) and photosynthetic capacity (Vcmax ) conformed to the proposed quantitative theory. Substantial hydraulic diversity was related to the trade-off between KS and vH . Leaf drought tolerance (inferred from turgor loss point, -Ψtlp ) increased with wood density, but the trade-off between hydraulic efficiency (KS ) and -Ψtlp was weak. Plant trait effects on vH were dominated by variation in KS , while effects of environment were dominated by variation in temperature. This research unifies hydraulics, photosynthesis and the leaf economics spectrum in a common theoretical framework, and suggests a route towards the integration of photosynthesis and hydraulics in land-surface models.
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Affiliation(s)
- Huiying Xu
- Ministry of Education Key Laboratory for Earth System ModelingDepartment of Earth System ScienceTsinghua UniversityBeijing100084China
- Joint Center for Global Change Studies (JCGCS)Beijing100875China
| | - Han Wang
- Ministry of Education Key Laboratory for Earth System ModelingDepartment of Earth System ScienceTsinghua UniversityBeijing100084China
- Joint Center for Global Change Studies (JCGCS)Beijing100875China
| | - I. Colin Prentice
- Ministry of Education Key Laboratory for Earth System ModelingDepartment of Earth System ScienceTsinghua UniversityBeijing100084China
- Department of Life SciencesGeorgina Mace Centre for the Living PlanetImperial College LondonSilwood Park Campus, Buckhurst RoadAscotSL5 7PYUK
- Department of Biological SciencesMacquarie UniversityNorth RydeNSW2109Australia
| | - Sandy P. Harrison
- Ministry of Education Key Laboratory for Earth System ModelingDepartment of Earth System ScienceTsinghua UniversityBeijing100084China
- School of Archaeology, Geography and Environmental Sciences (SAGES)University of ReadingReadingRG6 6AHUK
| | - Ian J. Wright
- Department of Biological SciencesMacquarie UniversityNorth RydeNSW2109Australia
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31
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Vargas G G, Brodribb TJ, Dupuy JM, González-M R, Hulshof CM, Medvigy D, Allerton TAP, Pizano C, Salgado-Negret B, Schwartz NB, Van Bloem SJ, Waring BG, Powers JS. Beyond leaf habit: generalities in plant function across 97 tropical dry forest tree species. New Phytol 2021; 232:148-161. [PMID: 34171131 DOI: 10.1111/nph.17584] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 06/15/2021] [Indexed: 05/12/2023]
Abstract
Leaf habit has been hypothesized to define a linkage between the slow-fast plant economic spectrum and the drought resistance-avoidance trade-off in tropical forests ('slow-safe vs fast-risky'). However, variation in hydraulic traits as a function of leaf habit has rarely been explored for a large number of species. We sampled leaf and branch functional traits of 97 tropical dry forest tree species from four sites to investigate whether patterns of trait variation varied consistently in relation to leaf habit along the 'slow-safe vs fast-risky' trade-off. Leaf habit explained from 0% to 43.69% of individual trait variation. We found that evergreen and semi-deciduous species differed in their location along the multivariate trait ordination when compared to deciduous species. While deciduous species showed consistent trait values, evergreen species trait values varied as a function of the site. Last, trait values varied in relation to the proportion of deciduous species in the plant community. We found that leaf habit describes the strategies that define drought avoidance and plant economics in tropical trees. However, leaf habit alone does not explain patterns of trait variation, which suggests quantifying site-specific or species-specific uncertainty in trait variation as the way forward.
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Affiliation(s)
- German Vargas G
- Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, 55108, USA
| | - Tim J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, TAS, 7001, Australia
| | - Juan M Dupuy
- Centro de Investigación Científica de Yucatán, Unidad de Recursos Naturales, Calle 43 # 130 entre 32 y 34, Col. Chuburná de Hidalgo, Mérida, Yucatán, CP 97205, México
| | - Roy González-M
- Programa Ciencias de la Biodiversidad, Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Carrera #1 16-20, Bogotá, 111311, Colombia
| | - Catherine M Hulshof
- Department of Biology, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - David Medvigy
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Tristan A P Allerton
- Baruch Institute of Coastal Ecology and Forest Science, Clemson University, PO Box 596, Georgetown, SC, 29442, USA
| | - Camila Pizano
- Departamento de Biología, Universidad ICESI, Calle 18 # 122-135, Cali, 760031, Colombia
| | - Beatriz Salgado-Negret
- Departamento de Biología, Universidad Nacional de Colombia, sede Bogotá, Carrera 30 Calle 45, Bogotá, 111321, Colombia
| | - Naomi B Schwartz
- Department of Geography, University of British Columbia, Vancouver, BC, V6T 1Z2, Canada
| | - Skip J Van Bloem
- Baruch Institute of Coastal Ecology and Forest Science, Clemson University, PO Box 596, Georgetown, SC, 29442, USA
| | - Bonnie G Waring
- Department of Biology, Utah State University, Logan, UT, 84322, USA
| | - Jennifer S Powers
- Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, 55108, USA
- Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, MN, 55108, USA
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32
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Varner JM, Hood SM, Aubrey DP, Yedinak K, Hiers JK, Jolly WM, Shearman TM, McDaniel JK, O’Brien JJ, Rowell EM. Tree crown injury from wildland fires: causes, measurement and ecological and physiological consequences. New Phytol 2021; 231:1676-1685. [PMID: 34105789 PMCID: PMC8546925 DOI: 10.1111/nph.17539] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 05/22/2021] [Indexed: 06/12/2023]
Abstract
The dead foliage of scorched crowns is one of the most conspicuous signatures of wildland fires. Globally, crown scorch from fires in savannas, woodlands and forests causes tree stress and death across diverse taxa. The term crown scorch, however, is inconsistently and ambiguously defined in the literature, causing confusion and conflicting interpretation of results. Furthermore, the underlying mechanisms causing foliage death from fire are poorly understood. The consequences of crown scorch - alterations in physiological, biogeochemical and ecological processes and ecosystem recovery pathways - remain largely unexamined. Most research on the topic assumes the mechanism of leaf and bud death is exposure to lethal air temperatures, with few direct measurements of lethal heating thresholds. Notable information gaps include how energy transfer injures and kills leaves and buds, how nutrients, carbohydrates, and hormones respond, and what physiological consequences lead to mortality. We clarify definitions to encourage use of unified terminology for foliage and bud necrosis resulting from fire. We review the current understanding of the physical mechanisms driving foliar injury, discuss the physiological responses, and explore novel ecological consequences of crown injury from fire. From these elements, we propose research needs for the increasingly interdisciplinary study of fire effects.
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Affiliation(s)
| | - Sharon M. Hood
- USDA Forest ServiceRocky Mountain Research StationMissoulaMT59808USA
| | - Doug. P. Aubrey
- Warnell School of Forestry & Natural ResourcesSavannah River Ecology LaboratoryUniversity of GeorgiaAikenSC29802USA
| | - Kara Yedinak
- USDA Forest Products LaboratoryMadisonWI53726USA
| | | | - W. Matthew Jolly
- USDA Forest ServiceRocky Mountain Research StationMissoulaMT59808USA
| | | | - Jennifer K. McDaniel
- Warnell School of Forestry & Natural ResourcesSavannah River Ecology LaboratoryUniversity of GeorgiaAikenSC29802USA
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Trabi CL, Pereira L, Guan X, Miranda MT, Bittencourt PRL, Oliveira RS, Ribeiro RV, Jansen S. A User Manual to Measure Gas Diffusion Kinetics in Plants: Pneumatron Construction, Operation, and Data Analysis. Front Plant Sci 2021; 12:633595. [PMID: 34163496 PMCID: PMC8216216 DOI: 10.3389/fpls.2021.633595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 05/12/2021] [Indexed: 05/17/2023]
Abstract
The Pneumatron device measures gas diffusion kinetics in the xylem of plants. The device provides an easy, low-cost, and powerful tool for research on plant water relations and gas exchange. Here, we describe in detail how to construct and operate this device to estimate embolism resistance of angiosperm xylem, and how to analyse pneumatic data. Simple and more elaborated ways of constructing a Pneumatron are shown, either using wires, a breadboard, or a printed circuit board. The instrument is based on an open-source hardware and software system, which allows users to operate it in an automated or semi-automated way. A step-by-step manual and a troubleshooting section are provided. An excel spreadsheet and an R-script are also presented for fast and easy data analysis. This manual aims at helping users to avoid common mistakes, such as unstable measurements of the minimum and maximum amount of gas discharged from xylem tissue, which has major consequences for estimating embolism resistance. Major advantages of the Pneumatron device include its automated and accurate measurements of gas diffusion rates, including highly precise measurements of the gas volume in intact, embolised conduits. It is currently unclear if the method can also be applied to woody monocots, gymnosperm species that possess torus-margo pit membranes, or to herbaceous species.
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Affiliation(s)
| | - Luciano Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
- Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), Campinas, Brazil
- Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Xinyi Guan
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - Marcela T. Miranda
- Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), Campinas, Brazil
| | | | - Rafael S. Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Rafael V. Ribeiro
- Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
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34
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Rowland L, Martínez-Vilalta J, Mencuccini M. Hard times for high expectations from hydraulics: predicting drought-induced forest mortality at landscape scales remains a challenge. New Phytol 2021; 230:1685-1687. [PMID: 33797779 DOI: 10.1111/nph.17317] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Affiliation(s)
- Lucy Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QE, UK
| | - Jordi Martínez-Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès), 08193, Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), 08193, Spain
| | - Maurizio Mencuccini
- CREAF, Bellaterra (Cerdanyola del Vallès), 08193, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, 08010, Spain
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35
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Domec JC, King JS, Carmichael MJ, Overby AT, Wortemann R, Smith WK, Miao G, Noormets A, Johnson DM. Aquaporins, and not changes in root structure, provide new insights into physiological responses to drought, flooding, and salinity. J Exp Bot 2021; 72:4489-4501. [PMID: 33677600 DOI: 10.1093/jxb/erab100] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 02/27/2021] [Indexed: 06/12/2023]
Abstract
The influence of aquaporin (AQP) activity on plant water movement remains unclear, especially in plants subject to unfavorable conditions. We applied a multitiered approach at a range of plant scales to (i) characterize the resistances controlling water transport under drought, flooding, and flooding plus salinity conditions; (ii) quantify the respective effects of AQP activity and xylem structure on root (Kroot), stem (Kstem), and leaf (Kleaf) conductances; and (iii) evaluate the impact of AQP-regulated transport capacity on gas exchange. We found that drought, flooding, and flooding plus salinity reduced Kroot and root AQP activity in Pinus taeda, whereas Kroot of the flood-tolerant Taxodium distichum did not decline under flooding. The extent of the AQP control of transport efficiency varied among organs and species, ranging from 35-55% in Kroot to 10-30% in Kstem and Kleaf. In response to treatments, AQP-mediated inhibition of Kroot rather than changes in xylem acclimation controlled the fluctuations in Kroot. The reduction in stomatal conductance and its sensitivity to vapor pressure deficit were direct responses to decreased whole-plant conductance triggered by lower Kroot and larger resistance belowground. Our results provide new mechanistic and functional insights on plant hydraulics that are essential to quantifying the influences of future stress on ecosystem function.
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Affiliation(s)
- Jean-Christophe Domec
- Bordeaux Sciences AGRO, UMR1391 ISPA INRA, 1 Cours du général de Gaulle, 33175 Gradignan Cedex, France
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
| | - John S King
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27606, USA
| | - Mary J Carmichael
- Departments of Biology and Environmental Studies, Hollins University, Roanoke, VA 24020, USA
| | - Anna Treado Overby
- Planning, Design and the Built Environment, Clemson University, Clemson, SC 29634, USA
| | - Remi Wortemann
- Université de Lorraine, INRA, UMR 1434 Silva, 54000, Nancy, France
| | - William K Smith
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Guofang Miao
- School of Geographical Sciences, Fujian Normal University, Fuzhou, FJ-350007, PR China
| | - Asko Noormets
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX 77843, USA
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA
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36
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Koçillari L, Olson ME, Suweis S, Rocha RP, Lovison A, Cardin F, Dawson TE, Echeverría A, Fajardo A, Lechthaler S, Martínez-Pérez C, Marcati CR, Chung KF, Rosell JA, Segovia-Rivas A, Williams CB, Petrone-Mendoza E, Rinaldo A, Anfodillo T, Banavar JR, Maritan A. The Widened Pipe Model of plant hydraulic evolution. Proc Natl Acad Sci U S A 2021; 118:e2100314118. [PMID: 34039710 DOI: 10.1073/pnas.2100314118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Shaping global water and carbon cycles, plants lift water from roots to leaves through xylem conduits. The importance of xylem water conduction makes it crucial to understand how natural selection deploys conduit diameters within and across plants. Wider conduits transport more water but are likely more vulnerable to conduction-blocking gas embolisms and cost more for a plant to build, a tension necessarily shaping xylem conduit diameters along plant stems. We build on this expectation to present the Widened Pipe Model (WPM) of plant hydraulic evolution, testing it against a global dataset. The WPM predicts that xylem conduits should be narrowest at the stem tips, widening quickly before plateauing toward the stem base. This universal profile emerges from Pareto modeling of a trade-off between just two competing vectors of natural selection: one favoring rapid widening of conduits tip to base, minimizing hydraulic resistance, and another favoring slow widening of conduits, minimizing carbon cost and embolism risk. Our data spanning terrestrial plant orders, life forms, habitats, and sizes conform closely to WPM predictions. The WPM highlights carbon economy as a powerful vector of natural selection shaping plant function. It further implies that factors that cause resistance in plant conductive systems, such as conduit pit membrane resistance, should scale in exact harmony with tip-to-base conduit widening. Furthermore, the WPM implies that alterations in the environments of individual plants should lead to changes in plant height, for example, shedding terminal branches and resprouting at lower height under drier climates, thus achieving narrower and potentially more embolism-resistant conduits.
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37
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McElrone AJ, Manuck CM, Brodersen CR, Patakas A, Pearsall KR, Williams LE. Functional hydraulic sectoring in grapevines as evidenced by sap flow, dye infusion, leaf removal and micro-computed tomography. AoB Plants 2021; 13:plab003. [PMID: 33841756 PMCID: PMC8023307 DOI: 10.1093/aobpla/plab003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 01/08/2021] [Indexed: 05/24/2023]
Abstract
The supply of water to a plant canopy is dependent on the xylem pathway connecting roots to leaves. In some plants, sectored xylem pathways can restrict resource distribution, resulting in variable quality of organs in the shoots, yet little is known about the effects of sectoring in crop cultivars. In this study, we combined sap flow measurements and infusion of xylem-specific dyes to document functional conductive area and flow pathways from roots to shoots of 20-year-old Thompson Seedless and 8-year-old Chardonnay grapevines. Sap flow measurements and dye infusion demonstrated that water flowed predominantly in discrete xylem (visually identifiable from the trunk surface) sectors along the trunk axis, each supplying limited portions of the canopy. Functional conductive area in the trunk was proportional to that in the shoots even though sector size varied considerably between vines. Leaf area removal experiments further demonstrated sectoring in grapevines; sap flow decreased by >90 % in trunk sectors connected to excised shoots while it remained constant in trunk sectors supplying intact portions of the canopy. Despite the functional sectoring in grapevines, a high degree of interconnectivity of trunk xylem in the tangential direction was confirmed with synchrotron-based micro-computed tomography (microCT) and dye crossover infusion studies. Fruit attached to dyed canes was also similarly sectored; no clusters exhibited dye on non-dyed canes, while 97 % of clusters attached to dyed canes exhibited dye infusion. The dye travelled down the cluster rachis and appeared to accumulate at the pedicel/berry junction, but only on dyed canes. These findings suggest that xylem in grapevine trunks is integrated anatomically, but functions in a sectored manner due to high axial hydraulic conductivity. The functional sectoring of grapevine xylem documented here has important implications for management practices in vineyards and for fruit cluster uniformity within single grapevine.
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Affiliation(s)
- A J McElrone
- USDA-ARS, Crops Pathology and Genetics Research Unit, Davis, CA 95616, USA
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
| | - C M Manuck
- USDA-ARS, Crops Pathology and Genetics Research Unit, Davis, CA 95616, USA
| | | | - A Patakas
- University of Ioannina, Ioannina, 451 10, Greece
| | - K R Pearsall
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
| | - L E Williams
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
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38
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Barillot R, De Swaef T, Combes D, Durand JL, Escobar-Gutiérrez AJ, Martre P, Perrot C, Roy E, Frak E. Leaf elongation response to blue light is mediated by stomatal-induced variations in transpiration in Festuca arundinacea. J Exp Bot 2021; 72:2642-2656. [PMID: 33326568 DOI: 10.1093/jxb/eraa585] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
Reduced blue light irradiance is known to enhance leaf elongation rate (LER) in grasses, but the mechanisms involved have not yet been elucidated. We investigated whether leaf elongation response to reduced blue light could be mediated by stomata-induced variations of plant transpiration. Two experiments were carried out on tall fescue in order to monitor LER and transpiration under reduced blue light irradiance. Additionally, LER dynamics were compared with those observed in the response to vapour pressure deficit (VPD)-induced variations of transpiration. Finally, we developed a model of water flow within a tiller to simulate the observed short-term response of LER to various transpiration regimes. LER dramatically increased in response to blue light reduction and then reached new steady states, which remained higher than the control. Reduced blue light triggered a simultaneous stomatal closure which induced an immediate decrease of leaf transpiration. The hydraulic model of leaf elongation accurately predicted the LER response to blue light and VPD, resulting from an increase in the growth-induced water potential gradient in the leaf growth zone. Our results suggest that the blue light signal is sensed by stomata of expanded leaves and transduced to the leaf growth zone through the hydraulic architecture of the tiller.
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Affiliation(s)
| | - Tom De Swaef
- Plant Sciences Unit, Institute for Agricultural and Fisheries Research (ILVO), Melle, Belgium
| | | | | | | | - Pierre Martre
- INRAE, Univ Montpellier, Montpellier SupAgro, UMR LEPSE, Montpellier, France
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39
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Olson ME, Anfodillo T, Gleason SM, McCulloh KA. Tip-to-base xylem conduit widening as an adaptation: causes, consequences, and empirical priorities. New Phytol 2021; 229:1877-1893. [PMID: 32984967 DOI: 10.1111/nph.16961] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/14/2020] [Indexed: 06/11/2023]
Abstract
In the stems of terrestrial vascular plants studied to date, the diameter of xylem water-conducting conduits D widens predictably with distance from the stem tip L approximating D ∝ Lb , with b ≈ 0.2. Because conduit diameter is central for conductance, it is essential to understand the cause of this remarkably pervasive pattern. We give reason to suspect that tip-to-base conduit widening is an adaptation, favored by natural selection because widening helps minimize the increase in hydraulic resistance that would otherwise occur as an individual stem grows longer and conductive path length increases. Evidence consistent with adaptation includes optimality models that predict the 0.2 exponent. The fact that this prediction can be made with a simple model of a single capillary, omitting much biological detail, itself makes numerous important predictions, e.g. that pit resistance must scale isometrically with conduit resistance. The idea that tip-to-base conduit widening has a nonadaptive cause, with temperature, drought, or turgor limiting the conduit diameters that plants are able to produce, is less consistent with the data than an adaptive explanation. We identify empirical priorities for testing the cause of tip-to-base conduit widening and underscore the need to study plant hydraulic systems leaf to root as integrated wholes.
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Affiliation(s)
- Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Mexico City, 04510, Mexico
| | - Tommaso Anfodillo
- Department Territorio e Sistemi Agro-Forestali, University of Padova, Legnaro (PD), 35020, Italy
| | - Sean M Gleason
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, CO, 80526, USA
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO, 80523, USA
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40
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Almeida WL, Ávila RT, Pérez-Molina JP, Barbosa ML, Marçal DMS, de Souza RPB, Martino PB, Cardoso AA, Martins SCV, DaMatta FM. The interplay between irrigation and fruiting on branch growth and mortality, gas exchange and water relations of coffee trees. Tree Physiol 2021; 41:35-49. [PMID: 32879972 DOI: 10.1093/treephys/tpaa116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
The overall coordination between gas exchanges and plant hydraulics may be affected by soil water availability and source-to-sink relationships. Here we evaluated how branch growth and mortality, leaf gas exchange and metabolism are affected in coffee (Coffea arabica L.) trees by drought and fruiting. Field-grown plants were irrigated or not, and maintained with full or no fruit load. Under mild water deficit, irrigation per se did not significantly impact growth but markedly reduced branch mortality in fruiting trees, despite similar leaf assimilate pools and water status. Fruiting increased net photosynthetic rate in parallel with an enhanced stomatal conductance, particularly in irrigated plants. Mesophyll conductance and maximum RuBisCO carboxylation rate remained unchanged across treatments. The increased stomatal conductance in fruiting trees over nonfruiting ones was unrelated to internal CO2 concentration, foliar abscisic acid (ABA) levels or differential ABA sensitivity. However, stomatal conductance was associated with higher stomatal density, lower stomatal sensitivity to vapor pressure deficit, and higher leaf hydraulic conductance and capacitance. Increased leaf transpiration rate in fruiting trees was supported by coordinated alterations in plant hydraulics, which explained the maintenance of plant water status. Finally, by preventing branch mortality, irrigation can mitigate biennial production fluctuations and improve the sustainability of coffee plantations.
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Affiliation(s)
- Wellington L Almeida
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Viçosa 36570-900, Brazil
| | - Rodrigo T Ávila
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Viçosa 36570-900, Brazil
| | - Junior P Pérez-Molina
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Viçosa 36570-900, Brazil
- Laboratorio de Ecología Funcional y Ecosistemas Tropicales, Escuela de Ciencias Biológicas, Universidad Nacional Costa Rica, Avenida 1, Calle 9, Heredia 863000, Costa Rica
| | - Marcela L Barbosa
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Viçosa 36570-900, Brazil
| | - Dinorah M S Marçal
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Viçosa 36570-900, Brazil
| | - Raylla P B de Souza
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Viçosa 36570-900, Brazil
| | - Pedro B Martino
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Viçosa 36570-900, Brazil
| | - Amanda A Cardoso
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Viçosa 36570-900, Brazil
| | - Samuel C V Martins
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Viçosa 36570-900, Brazil
| | - Fábio M DaMatta
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Viçosa 36570-900, Brazil
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41
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Strock CF, Burridge JD, Niemiec MD, Brown KM, Lynch JP. Root metaxylem and architecture phenotypes integrate to regulate water use under drought stress. Plant Cell Environ 2021; 44:49-67. [PMID: 32839986 DOI: 10.1111/pce.13875] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 07/30/2020] [Accepted: 08/16/2020] [Indexed: 05/06/2023]
Abstract
At the genus and species level, variation in root anatomy and architecture may interact to affect strategies of drought avoidance. To investigate this idea, root anatomy and architecture of the drought-sensitive common bean (Phaseolus vulgaris) and drought-adapted tepary bean (Phaseolus acutifolius) were analyzed in relation to water use under terminal drought. Intraspecific variation for metaxylem anatomy and axial conductance was found in the roots of both species. Genotypes with high-conductance root metaxylem phenotypes acquired and transpired more water per unit leaf area, shoot mass, and root mass than genotypes with low-conductance metaxylem phenotypes. Interspecific variation in root architecture and root depth was observed where P. acutifolius has a deeper distribution of root length than P. vulgaris. In the deeper-rooted P. acutifolius, genotypes with high root conductance were better able to exploit deep soil water than genotypes with low root axial conductance. Contrastingly, in the shallower-rooted P. vulgaris, genotypes with low root axial conductance had improved water status through conservation of soil moisture for sustained water capture later in the season. These results indicate that metaxylem morphology interacts with root system depth to determine a strategy of drought avoidance and illustrate synergism among architectural and anatomical phenotypes for root function.
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Affiliation(s)
- Christopher F Strock
- Department of Plant Science, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - James D Burridge
- Department of Plant Science, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Miranda D Niemiec
- Department of Plant Science, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kathleen M Brown
- Department of Plant Science, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Jonathan P Lynch
- Department of Plant Science, The Pennsylvania State University, University Park, Pennsylvania, USA
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42
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Toca A, Villar-Salvador P, Oliet JA, Jacobs DF. Normalization criteria determine the interpretation of nitrogen effects on the root hydraulics of pine seedlings. Tree Physiol 2020; 40:1381-1391. [PMID: 32483620 DOI: 10.1093/treephys/tpaa068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
Plant hydraulics is key for plant survival and growth because it is linked to gas exchange and drought resistance. Although the environment influences plant hydraulics, there is no clear consensus on the effect of nitrogen (N) supply, which may be, in part, due to different hydraulic conductance normalization criteria and studied species. The objective of this study was to compare the variation of root hydraulic properties using several normalization criteria in four pine species in response to three contrasting N fertilization regimes. We studied four closely related, yet ecologically distinct species: Pinus nigra J.F. Arnold, Pinus pinaster Ait., Pinus pinea L. and Pinus halepensis Mill. Root hydraulic conductance (Kh) was measured with a high-pressure flow meter, and values were normalized by total leaf area (leaf specific conductance, Kl), xylem cross-section area (xylem specific conductance, Ks), total root area (root specific conductance, Kr) and the area of fine roots (fine root specific conductance, Kfr). Controlling for organ size differences allowed comparison of the hydraulic efficiency of roots to supply or absorb water among fertilization treatments and species. The effect of N on the root hydraulic efficiency depended on the normalization criteria. Increasing N availability reduced Kl and Ks, but increased Kh, Kr and especially Kfr. The positive effect of N on Kr and Kfr was positively related to seedling relative growth rate and was also consistent with published results at the interspecific level, whereby plant hydraulics is positively linked to photosynthesis and transpiration rate and fast growth. In contrast, normalization by leaf area and xylem cross-sectional area (Kl and Ks) reflected opposite responses to Kr and Kfr. This indicates that the normalization criteria determine the interpretation of the effect of N on plant hydraulics, which can limit species and treatment comparisons.
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Affiliation(s)
- Andrei Toca
- Forest Ecology and Restoration Group, Departamento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, Madrid 28805, Spain
- Department of Forestry and Natural Resources, Hardwood Tree Improvement and Regeneration Center, Purdue University, 715 West State Street, West Lafayette, IN 47907, USA
| | - Pedro Villar-Salvador
- Forest Ecology and Restoration Group, Departamento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, Madrid 28805, Spain
| | - Juan A Oliet
- Departamento de Sistemas y Recursos Naturales, E.T.S. Ingenieros de Montes, Forestal y del Medio Natural, Universidad Politécnica de Ciudad Universitaria s/n, Madrid, 28040 Madrid, Spain
| | - Douglass F Jacobs
- Department of Forestry and Natural Resources, Hardwood Tree Improvement and Regeneration Center, Purdue University, 715 West State Street, West Lafayette, IN 47907, USA
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43
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De Kauwe MG, Medlyn BE, Ukkola AM, Mu M, Sabot MEB, Pitman AJ, Meir P, Cernusak LA, Rifai SW, Choat B, Tissue DT, Blackman CJ, Li X, Roderick M, Briggs PR. Identifying areas at risk of drought-induced tree mortality across South-Eastern Australia. Glob Chang Biol 2020; 26:5716-5733. [PMID: 32512628 DOI: 10.1111/gcb.15215] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
South-East Australia has recently been subjected to two of the worst droughts in the historical record (Millennium Drought, 2000-2009 and Big Dry, 2017-2019). Unfortunately, a lack of forest monitoring has made it difficult to determine whether widespread tree mortality has resulted from these droughts. Anecdotal observations suggest the Big Dry may have led to more significant tree mortality than the Millennium drought. Critically, to be able to robustly project future expected climate change effects on Australian vegetation, we need to assess the vulnerability of Australian trees to drought. Here we implemented a model of plant hydraulics into the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model. We parameterized the drought response behaviour of five broad vegetation types, based on a common garden dry-down experiment with species originating across a rainfall gradient (188-1,125 mm/year) across South-East Australia. The new hydraulics model significantly improved (~35%-45% reduction in root mean square error) CABLE's previous predictions of latent heat fluxes during periods of water stress at two eddy covariance sites in Australia. Landscape-scale predictions of the greatest percentage loss of hydraulic conductivity (PLC) of about 40%-60%, were broadly consistent with satellite estimates of regions of the greatest change in both droughts. In neither drought did CABLE predict that trees would have reached critical PLC in widespread areas (i.e. it projected a low mortality risk), although the model highlighted critical levels near the desert regions of South-East Australia where few trees live. Overall, our experimentally constrained model results imply significant resilience to drought conferred by hydraulic function, but also highlight critical data and scientific gaps. Our approach presents a promising avenue to integrate experimental data and make regional-scale predictions of potential drought-induced hydraulic failure.
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Affiliation(s)
- Martin G De Kauwe
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
- Evolution & Ecology Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Anna M Ukkola
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
| | - Mengyuan Mu
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Manon E B Sabot
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
- Evolution & Ecology Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Andrew J Pitman
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Patrick Meir
- Research School of Biology, The Australian National University, Acton, ACT, Australia
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Qld, Australia
| | - Sami W Rifai
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Chris J Blackman
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Ximeng Li
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Michael Roderick
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
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44
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Sanchez-Martinez P, Martínez-Vilalta J, Dexter KG, Segovia RA, Mencuccini M. Adaptation and coordinated evolution of plant hydraulic traits. Ecol Lett 2020; 23:1599-1610. [PMID: 32808458 DOI: 10.1111/ele.13584] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/21/2020] [Accepted: 07/07/2020] [Indexed: 12/30/2022]
Abstract
Hydraulic properties control plant responses to climate and are likely to be under strong selective pressure, but their macro-evolutionary history remains poorly characterised. To fill this gap, we compiled a global dataset of hydraulic traits describing xylem conductivity (Ks ), xylem resistance to embolism (P50), sapwood allocation relative to leaf area (Hv) and drought exposure (ψmin ), and matched it with global seed plant phylogenies. Individually, these traits present medium to high levels of phylogenetic signal, partly related to environmental selective pressures shaping lineage evolution. Most of these traits evolved independently of each other, being co-selected by the same environmental pressures. However, the evolutionary correlations between P50 and ψmin and between Ks and Hv show signs of deeper evolutionary integration because of functional, developmental or genetic constraints, conforming to evolutionary modules. We do not detect evolutionary integration between conductivity and resistance to embolism, rejecting a hardwired trade-off for this pair of traits.
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Affiliation(s)
- Pablo Sanchez-Martinez
- CREAF, Cerdanyola del Valles, Barcelona, 08193, Spain.,Universitat Autònoma de Barcelona, Cerdanyola del Valles, Barcelona, 08193, Spain
| | - Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Valles, Barcelona, 08193, Spain.,Universitat Autònoma de Barcelona, Cerdanyola del Valles, Barcelona, 08193, Spain
| | - Kyle G Dexter
- School of GeoSciences, University of Edinburgh, Edinburgh, UK.,Royal Botanic Garden Edinburgh, Edinburgh, UK
| | - Ricardo A Segovia
- School of GeoSciences, University of Edinburgh, Edinburgh, UK.,Instituto de Ecología y Biodiversidad, Santiago, Chile
| | - Maurizio Mencuccini
- CREAF, Cerdanyola del Valles, Barcelona, 08193, Spain.,ICREA, Pg. Lluís Companys 23, Barcelona, 08010, Spain
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45
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Wilson JP, White JD, Montañez IP, DiMichele WA, McElwain JC, Poulsen CJ, Hren MT. Carboniferous plant physiology breaks the mold. New Phytol 2020; 227:667-679. [PMID: 32267976 DOI: 10.1111/nph.16460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 11/17/2019] [Indexed: 06/11/2023]
Abstract
How plants have shaped Earth surface feedbacks over geologic time is a key question in botanical and geological inquiry. Recent work has suggested that biomes during the Carboniferous Period contained plants with extraordinary physiological capacity to shape their environment, contradicting the previously dominant view that plants only began to actively moderate the Earth's surface with the rise of angiosperms during the Mesozoic Era. A recently published Viewpoint disputes this recent work, thus here, we document in detail, the mechanistic underpinnings of our modeling and illustrate the extraordinary ecophysiological nature of Carboniferous plants.
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Affiliation(s)
- Jonathan P Wilson
- Department of Environmental Studies, Haverford College, Haverford, PA, 19041, USA
| | - Joseph D White
- Department of Biology, Baylor University, Waco, TX, 76798, USA
| | - Isabel P Montañez
- Department of Earth and Planetary Sciences, University of California, Davis, CA, 95616, USA
| | - William A DiMichele
- Department of Paleobiology, Smithsonian Museum of Natural History, Washington, DC, 20560, USA
| | - Jennifer C McElwain
- Department of Botany, School of Natural Sciences, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
| | - Christopher J Poulsen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Michael T Hren
- Center for Integrative Geosciences, University of Connecticut, Storrs, CT, 06269, USA
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46
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Skelton RP. Quantifying plant hydraulic function becomes a tall order. J Exp Bot 2020; 71:3927-3929. [PMID: 32628768 PMCID: PMC7337181 DOI: 10.1093/jxb/eraa240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This article comments on:
Soriano D, Echeverría A, Anfodillo T, Rosell JA, Olson ME. 2020. Hydraulic traits vary following tip-to-base conduit widening in vascular plants. Journal of Experimental Botany 71, 4232–4242.
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Affiliation(s)
- Robert P Skelton
- South African Environmental Observation Network, Fynbos Node, Newlands, Cape Town, South Africa
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47
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Souza Dias A, Oliveira RS, Martins FR. Costs and benefits of gas inside wood and its relationship with anatomical traits: a contrast between trees and lianas. Tree Physiol 2020; 40:856-868. [PMID: 32186732 DOI: 10.1093/treephys/tpaa034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 02/25/2020] [Accepted: 03/13/2020] [Indexed: 06/10/2023]
Abstract
Gas inside wood plays an important role in plant functioning, but there has been no study examining the adaptive nature of gas inside wood across plants differing in biomechanical demands. Using a comparative approach, we measured gas volumetric content, xylem's anatomical traits and wood density of 15 tree and 16 liana species, to test whether gas content varies between these plant types strongly differing in their biomechanical demands. We asked (i) whether trees and lianas differ in gas content and (ii) how anatomical traits and wood density are related to gas content. Lianas had significantly less gas content in their branches compared with tree species. In tree species, gas content scaled positively with fiber, vessel and xylem cross-sectional area and fiber and vessel diameter, and negatively with dry-mass density. When pooling trees and lianas together, fiber cross-sectional area was the strongest predictor of gas content, with higher xylem cross-sectional area of fiber associated with higher gas content. In addition, we showed, through a simple analytical model, that gas inside wood increases the minimum branch diameter needed to prevent rupture, and this effect was stronger on trees compared with lianas. Our results support the view that gas inside wood plays an important role in the evolution of biomechanical functioning in different plant forms. Gas inside wood may also play an important role in physiological activities such as water transport, storage, photosynthesis and respiration, but it is still unknown whether these roles are or are not secondary to the mechanical support.
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Affiliation(s)
- Arildo Souza Dias
- Plant Biology Graduate Course, Department of Plant Biology, Institute of Biology, Monteiro Lobato Street, 255, University of Campinas - UNICAMP, PO Box 6109, Campinas, SP 13083-970, Brazil
- Institute for Physical Geography, Goethe University, Altenhöferallee 1, Frankfurt am Main 60438, Germany
| | - Rafael Silva Oliveira
- Department of Plant Biology, Institute of Biology, Monteiro Lobato Street, 255, University of Campinas - UNICAMP, PO Box 6109, Campinas, SP 13083-970, Brazil
| | - Fernando Roberto Martins
- Department of Plant Biology, Institute of Biology, Monteiro Lobato Street, 255, University of Campinas - UNICAMP, PO Box 6109, Campinas, SP 13083-970, Brazil
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48
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Megonigal JP, Brewer PE, Knee KL. Radon as a natural tracer of gas transport through trees. New Phytol 2020; 225:1470-1475. [PMID: 31665818 DOI: 10.1111/nph.16292] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 10/22/2019] [Indexed: 06/10/2023]
Abstract
Trees are sources, sinks, and conduits for gas exchange between the atmosphere and soil, and effectively link these terrestrial realms in a soil-plant-atmosphere continuum. We demonstrated that naturally produced radon-222 (222 Rn) gas has the potential to disentangle the biotic and physical processes that regulate gas transfer between soils or plants and the atmosphere in field settings where exogenous tracer applications are challenging. Patterns in stem radon emissions across tree species, seasons, and diurnal periods suggest that plant transport of soil gases is controlled by plant hydraulics, whether by diffusion or mass flow via transpiration. We establish for the first time that trees emit soil gases during the night when transpiration rates are negligible, suggesting that axial diffusion is an important and understudied mechanism of plant and soil gas transmission.
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Affiliation(s)
| | - Paul E Brewer
- Smithsonian Environmental Research Center, Edgewater, MD, 20754, USA
| | - Karen L Knee
- Smithsonian Environmental Research Center, Edgewater, MD, 20754, USA
- Department of Environmental Science, American University, Washington, DC, 20016, USA
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49
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Zenes N, Kerr KL, Trugman AT, Anderegg WRL. Competition and Drought Alter Optimal Stomatal Strategy in Tree Seedlings. Front Plant Sci 2020; 11:478. [PMID: 32457769 PMCID: PMC7227391 DOI: 10.3389/fpls.2020.00478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 03/31/2020] [Indexed: 05/17/2023]
Abstract
A better understanding of plant stomatal strategies holds strong promise for improving predictions of vegetation responses to drought because stomata are the primary mechanism through which plants mitigate water stress. It has been assumed that plants regulate stomata to maintain a constant marginal water use efficiency and forego carbon gain when water is scarce. However, recent hypotheses pose that plants maximize carbon assimilation while also accounting for the risk of hydraulic damage via cavitation and hydraulic failure. This "gain-risk" framework incorporates competition in stomatal regulation because it takes into account that neighboring plants can "steal" unused water. This study utilizes stomatal models representing both the water use efficiency and carbon-maximization frameworks, and empirical data from three species in a potted growth chamber experiment, to investigate the effects of drought and competition on seedling stomatal strategy. We found that drought and competition responses in the empirical data were best explained by the carbon-maximization hypothesis and that both drought and competition affected stomatal strategy. Interestingly, stomatal responses differed substantially by species, with seedlings employing a riskier strategy when planted with a high water use competitor, and seedlings employing a more conservative strategy when planted with a low water use competitor. Lower water users in general had less stomatal sensitivity to decreasing Ψ L compared to moderate to high water users. Repeated water stress also resulted in legacy effects on plant stomatal behavior, increasing stomatal sensitivity (i.e., conservative behavior) even when the seedling was returned to well-watered conditions. These results indicate that stomatal strategies are dynamic and change with climate and competition stressors. Therefore, incorporating mechanisms that allow for stomatal behavioral changes in response to water limitation may be an important step to improving carbon cycle projections in coupled climate-Earth system models.
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Affiliation(s)
- Nicole Zenes
- School of Biological Sciences, University of Utah, Salt Lake City, UT, United States
- *Correspondence: Nicole Zenes, ;
| | - Kelly L. Kerr
- School of Biological Sciences, University of Utah, Salt Lake City, UT, United States
| | - Anna T. Trugman
- School of Biological Sciences, University of Utah, Salt Lake City, UT, United States
- Department of Geography, University of California, Santa Barbara, Santa Barbara, CA, United States
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50
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Pereira L, Bittencourt PRL, Pacheco VS, Miranda MT, Zhang Y, Oliveira RS, Groenendijk P, Machado EC, Tyree MT, Jansen S, Rowland L, Ribeiro RV. The Pneumatron: An automated pneumatic apparatus for estimating xylem vulnerability to embolism at high temporal resolution. Plant Cell Environ 2020; 43:131-142. [PMID: 31461536 DOI: 10.1111/pce.13647] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 08/16/2019] [Accepted: 08/20/2019] [Indexed: 05/29/2023]
Abstract
Xylem vulnerability to embolism represents an important trait to determine species distribution patterns and drought resistance. However, estimating embolism resistance frequently requires time-consuming and ambiguous hydraulic lab measurements. Based on a recently developed pneumatic method, we present and test the "Pneumatron", a device that generates high time-resolution and fully automated vulnerability curves. Embolism resistance is estimated by applying a partial vacuum to extract air from an excised xylem sample, while monitoring the pressure change over time. Although the amount of gas extracted is strongly correlated with the percentage loss of xylem conductivity, validation of the Pneumatron was performed by comparison with the optical method for Eucalyptus camaldulensis leaves. The Pneumatron improved the precision of the pneumatic method considerably, facilitating the detection of small differences in the (percentage of air discharged [PAD] < 0.47%). Hence, the Pneumatron can directly measure the 50% PAD without any fitting of vulnerability curves. PAD and embolism frequency based on the optical method were strongly correlated (r2 = 0.93) for E. camaldulensis. By providing an open source platform, the Pneumatron represents an easy, low-cost, and powerful tool for field measurements, which can significantly improve our understanding of plant-water relations and the mechanisms behind embolism.
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Affiliation(s)
- Luciano Pereira
- Laboratory of Plant Physiology "Coaracy M. Franco", Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), Campinas, Brazil
- Laboratory of Crop Physiology, Department of Plant Biology, Institute of Biology, P.O. Box 6109, University of Campinas (UNICAMP), Campinas, 13083-970, Brazil
| | - Paulo R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
- Department of Plant Biology, Institute of Biology, P.O. Box 6109, UNICAMP, Campinas, 13083-970, Brazil
| | - Vinícius S Pacheco
- Department of Plant Biology, Institute of Biology, P.O. Box 6109, UNICAMP, Campinas, 13083-970, Brazil
| | - Marcela T Miranda
- Laboratory of Plant Physiology "Coaracy M. Franco", Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), Campinas, Brazil
| | - Ya Zhang
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, 89081, Germany
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, P.O. Box 6109, UNICAMP, Campinas, 13083-970, Brazil
| | - Peter Groenendijk
- Department of Plant Biology, Institute of Biology, P.O. Box 6109, UNICAMP, Campinas, 13083-970, Brazil
| | - Eduardo C Machado
- Laboratory of Plant Physiology "Coaracy M. Franco", Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), Campinas, Brazil
| | - Melvin T Tyree
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, 89081, Germany
| | - Lucy Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Rafael V Ribeiro
- Laboratory of Crop Physiology, Department of Plant Biology, Institute of Biology, P.O. Box 6109, University of Campinas (UNICAMP), Campinas, 13083-970, Brazil
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