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Dai Y, Wang L, Wan X. Maintenance of xylem hydraulic function during winter in the woody bamboo Phyllostachys propinqua McClure. PeerJ 2023; 11:e15979. [PMID: 37719123 PMCID: PMC10504893 DOI: 10.7717/peerj.15979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 08/08/2023] [Indexed: 09/19/2023] Open
Abstract
Background Frost is a common environmental stress for temperate plants. Xylem embolism occurs in many overwintering plants due to freeze-thaw cycles, so coping with freeze-thaw-induced embolisms is essential for the survival of temperate plants. Methods This study was conducted on Phyllostachys propinqua McClure, a woody bamboo species that was grown under natural frost conditions to explore its responses to winter embolisms. From autumn to the following spring, the following measurements were recorded: predawn branch and leaf embolism, branch and leaf relative water content (RWC), root pressure and soil temperature, xylem sap osmotic potential, branch and leaf electrolyte leakage (EL), branch nonstructural carbohydrate (NSC) content and leaf net photosynthetic rate. Results P. propinqua had a mean vessel diameter of 68.95 ±1.27 µm but did not suffer severe winter embolism, peaking around 60% in winter (January), with a distinct reduction in March when root pressure returned. Leaves had a more severe winter embolism, up to 90%. Leaf RWC was much lower in winter, and leaf EL was significantly higher than branch EL in all seasons. Root pressure remained until November when soil temperature reached 9 °C, then appeared again in March when soil temperatures increased from -6 °C (January) to 11 °C. Xylem sap osmotic potential decreased from autumn to winter, reaching a minimum in March, and then increasing again. Soluble sugar (SS) concentration increased throughout the winter, peaked in March, and then decreased. Conclusions These results suggest that (1) there is a hydraulic segmentation between the stem and leaf, which could prevent stem water loss and further embolization in winter; (2) maintenance of root pressure in early winter played an important role in reducing the effect of freeze-thaw cycles on the winter embolism; (3) the physiological process that resulted in a decrease in xylem sap osmotic potential and tissue water content, and an accumulation of SS associated with cold acclimation also aided in reducing the extent of freeze-thaw-induced embolism. All these strategies could be helpful for the maintenance of xylem hydraulic function of this bamboo species during winter.
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Affiliation(s)
- Yongxin Dai
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, China
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, China
| | - Lin Wang
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, China
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, China
| | - Xianchong Wan
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, China
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2
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Wood JD, Gu L, Hanson PJ, Frankenberg C, Sack L. The ecosystem wilting point defines drought response and recovery of a Quercus-Carya forest. GLOBAL CHANGE BIOLOGY 2023; 29:2015-2029. [PMID: 36600482 DOI: 10.1111/gcb.16582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 12/18/2022] [Accepted: 12/19/2022] [Indexed: 05/28/2023]
Abstract
Soil and atmospheric droughts increasingly threaten plant survival and productivity around the world. Yet, conceptual gaps constrain our ability to predict ecosystem-scale drought impacts under climate change. Here, we introduce the ecosystem wilting point (ΨEWP ), a property that integrates the drought response of an ecosystem's plant community across the soil-plant-atmosphere continuum. Specifically, ΨEWP defines a threshold below which the capacity of the root system to extract soil water and the ability of the leaves to maintain stomatal function are strongly diminished. We combined ecosystem flux and leaf water potential measurements to derive the ΨEWP of a Quercus-Carya forest from an "ecosystem pressure-volume (PV) curve," which is analogous to the tissue-level technique. When community predawn leaf water potential (Ψpd ) was above ΨEWP (=-2.0 MPa), the forest was highly responsive to environmental dynamics. When Ψpd fell below ΨEWP , the forest became insensitive to environmental variation and was a net source of carbon dioxide for nearly 2 months. Thus, ΨEWP is a threshold defining marked shifts in ecosystem functional state. Though there was rainfall-induced recovery of ecosystem gas exchange following soaking rains, a legacy of structural and physiological damage inhibited canopy photosynthetic capacity. Although over 16 growing seasons, only 10% of Ψpd observations fell below ΨEWP , the forest is commonly only 2-4 weeks of intense drought away from reaching ΨEWP , and thus highly reliant on frequent rainfall to replenish the soil water supply. We propose, based on a bottom-up analysis of root density profiles and soil moisture characteristic curves, that soil water acquisition capacity is the major determinant of ΨEWP , and species in an ecosystem require compatible leaf-level traits such as turgor loss point so that leaf wilting is coordinated with the inability to extract further water from the soil.
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Affiliation(s)
- Jeffrey D Wood
- School of Natural Resources, University of Missouri, Columbia, Missouri, USA
| | - Lianhong Gu
- Environmental Sciences Division and Climate Change Institute, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Paul J Hanson
- Environmental Sciences Division and Climate Change Institute, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Christian Frankenberg
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, USA
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3
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Losso A, Challis A, Gauthey A, Nolan RH, Hislop S, Roff A, Boer MM, Jiang M, Medlyn BE, Choat B. Canopy dieback and recovery in Australian native forests following extreme drought. Sci Rep 2022; 12:21608. [PMID: 36517498 PMCID: PMC9751299 DOI: 10.1038/s41598-022-24833-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022] Open
Abstract
In 2019, south-eastern Australia experienced its driest and hottest year on record, resulting in massive canopy dieback events in eucalypt dominated forests. A subsequent period of high precipitation in 2020 provided a rare opportunity to quantify the impacts of extreme drought and consequent recovery. We quantified canopy health and hydraulic impairment (native percent loss of hydraulic conductivity, PLC) of 18 native tree species growing at 15 sites that were heavily impacted by the drought both during and 8-10 months after the drought. Most species exhibited high PLC during drought (PLC:65.1 ± 3.3%), with no clear patterns across sites or species. Heavily impaired trees (PLC > 70%) showed extensive canopy browning. In the post-drought period, most surviving trees exhibited hydraulic recovery (PLC:26.1 ± 5.1%), although PLC remained high in some trees (50-70%). Regained hydraulic function (PLC < 50%) corresponded to decreased canopy browning indicating improved tree health. Similar drought (37.1 ± 4.2%) and post-drought (35.1 ± 4.4%) percentages of basal area with dead canopy suggested that trees with severely compromised canopies immediately after drought were not able to recover. This dataset provides insights into the impacts of severe natural drought on the health of mature trees, where hydraulic failure is a major contributor in canopy dieback and tree mortality during extreme drought events.
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Affiliation(s)
- Adriano Losso
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria.
| | - Anthea Challis
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Plant Ecology Research Laboratory PERL, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015, Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Rachael H Nolan
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- NSW Bushfire Risk Management Research Hub, Wollongong, NSW, Australia
| | - Samuel Hislop
- Forest Science, NSW Department of Primary Industries, Parramatta, NSW, 2150, Australia
| | - Adam Roff
- Department of Planning, Industry and Environment, Remote Sensing and Landscape Science, 26 Honeysuckle Drive, Newcastle, NSW, 2302, Australia
| | - Matthias M Boer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- NSW Bushfire Risk Management Research Hub, Wollongong, NSW, Australia
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- College of Life Sciences, Zhejiang University, 866 Yuhangtang Rd, Hangzhou, Zhejiang, China
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
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Aritsara ANA, Wang S, Li BN, Jiang X, Qie YD, Tan FS, Zhang QW, Cao KF. Divergent leaf and fine root "pressure-volume relationships" across habitats with varying water availability. PLANT PHYSIOLOGY 2022; 190:2246-2259. [PMID: 36047846 PMCID: PMC9706427 DOI: 10.1093/plphys/kiac403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
Fine roots and leaves, the direct interfaces of plants with their external environment along the soil-plant-atmosphere continuum, are at the front line to ensure plant adaptation to their growing habitat. This study aimed to compare the vulnerability to water deficit of fine roots and leaves of woody species from karst and mangrove forests-two water-stressed habitats-against that of timber and ornamental woody species grown in a well-watered common garden. Thus, pressure-volume curves in both organs of 37 species (about 12 species from each habitat) were constructed. Fine roots wilted at a less negative water potential than leaves in 32 species and before branch xylem lost 50% of its hydraulic conductivity in the 17 species with available data on branch xylem embolism resistance. Thus, turgor loss in fine roots can act as a hydraulic fuse mechanism against water stress. Mangroves had higher leaf resistance against wilting and lower leaf-specific area than the karst and common garden plants. Their fine roots had high specific root lengths (SRL) and high capacitance to buffer water stress. Karst species had high leaf bulk modulus, low leaf capacitance, and delayed fine root wilting. This study showed the general contribution of fine roots to the protection of the whole plant against underground water stress. Our findings highlight the importance of water storage in the leaves and fine roots of mangrove species and high tolerance to water deficit in the leaves of mangrove species and the fine roots of some karst species.
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Affiliation(s)
- Amy Ny Aina Aritsara
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
- College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Shuang Wang
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
- School of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Bei-Ni Li
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
- Department of Ecology, State Key Laboratory of Biocontrol and School of Ecology, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Jiang
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
- Office of Scientific Research and Development, Sichuan University, Chengdu 610065, China
| | - Ya-Dong Qie
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
| | - Feng-Sen Tan
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
- Research Institute of Forestry Chinese Academy of Forestry, Beijing 100091, China
| | - Qi-Wei Zhang
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
- College of Life Sciences, Guangxi Normal University, Guilin 541006, China
| | - Kun-Fang Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
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Wang L, Li J, Wang Y, Xue H, Dai Y, Han Y. Interactive effect between tree ageing and trunk-boring pest reduces hydraulics and carbon metabolism in Hippophae rhamnoides. AOB PLANTS 2022; 14:plac051. [PMID: 36545298 PMCID: PMC9762721 DOI: 10.1093/aobpla/plac051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 10/21/2022] [Indexed: 06/17/2023]
Abstract
Sea-buckthorn (Hippophae rhamnoides) is widely distributed across the Eurasian continent. Recently sea-buckthorn has shown premature ageing and decline when confronted with water deficiency and Holcocerus hippophaecolus damage in northwest China and the Loess Plateau region. However, the physiological process of sea-buckthorn senescence in response to drought and pest damage is still unknown. In this study, 4-year-old (4y), 15-year-old normal growth (15yN) and 15-year-old seriously moth-damaged sea-buckthorn plants (15yH) were used as the research objects. The growth of branches and roots, branch water potential and percentage loss of conductivity (PLC), branch vulnerability to embolism (quantified by P50, xylem water potential at 50 % of PLC), branch xylem parenchyma cell viability, photosynthesis and the non-structural carbohydrate (NSC) content in branches and roots in dry and wet seasons were measured. The results showed that the length, basal diameter of 1-year-old branches and the leaf area of 4y trees were significantly larger than that of 15yN and 15yH trees, and the fine root density of 15yH trees was significantly lower than that of 15yN trees in all measured areas. The branch-specific hydraulic conductivity of 15yN and 15yH trees was only 50.2 % and 12.3 % of that of 4y trees, and the P50 of 4y, 15yH and 15yN trees was -3.69 MPa, -2.71 MPa and -1.15 MPa, respectively. The midday water potential and photosynthetic rate were highest in 4y trees, followed by 15yN and then 15yH trees in both the dry season and wet seasons, while branch PLC declined in the opposite direction (15yH trees highest, 4y trees lowest). The degree of PLC repair within a day was highest in 4y trees, followed by 15yN and then 15yH trees, and the viability of xylem cells was consistent with this pattern. The branch xylem starch and NSC content of 4y and 15yN trees were significantly higher than that of 15yH trees in the dry season, and the root starch and NSC content of 4y trees were significantly higher than that of 15yH trees in the two seasons. The above results suggest that the hydraulic properties of the normal elderly and seriously pest-damaged sea-buckthorn were significantly worse than in juvenile plants. Narrower early wood width and vessel density, high embolism vulnerability and weak embolism repair capacity led to the decline in water-conducting ability, and similarly further affected photosynthesis and the root NSC content. The decline in xylem parenchyma cell viability was the main reason for the limited embolism repair in the branches.
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Affiliation(s)
- Lin Wang
- Corresponding author’s e-mail address:
| | - Junpeng Li
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Yang Wang
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Hao Xue
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Yongxin Dai
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Youzhi Han
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
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6
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Hajek P, Link RM, Nock CA, Bauhus J, Gebauer T, Gessler A, Kovach K, Messier C, Paquette A, Saurer M, Scherer-Lorenzen M, Rose L, Schuldt B. Mutually inclusive mechanisms of drought-induced tree mortality. GLOBAL CHANGE BIOLOGY 2022; 28:3365-3378. [PMID: 35246895 DOI: 10.1111/gcb.16146] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/16/2021] [Indexed: 06/14/2023]
Abstract
Unprecedented tree dieback across Central Europe caused by recent global change-type drought events highlights the need for a better mechanistic understanding of drought-induced tree mortality. Although numerous physiological risk factors have been identified, the importance of two principal mechanisms, hydraulic failure and carbon starvation, is still debated. It further remains largely unresolved how the local neighborhood composition affects individual mortality risk. We studied 9435 young trees of 12 temperate species planted in a diversity experiment in 2013 to assess how hydraulic traits, carbon dynamics, pest infestation, tree height and neighborhood competition influence individual mortality risk. Following the most extreme global change-type drought since record in 2018, one third of these trees died. Across species, hydraulic safety margins (HSMs) were negatively and a shift towards a higher sugar fraction in the non-structural carbohydrate (NSC) pool positively associated with mortality risk. Moreover, trees infested by bark beetles had a higher mortality risk, and taller trees a lower mortality risk. Most neighborhood interactions were beneficial, although neighborhood effects were highly species-specific. Species that suffered more from drought, especially Larix spp. and Betula spp., tended to increase the survival probability of their neighbors and vice versa. While severe tissue dehydration marks the final stage of drought-induced tree mortality, we show that hydraulic failure is interrelated with a series of other, mutually inclusive processes. These include shifts in NSC pools driven by osmotic adjustment and/or starch depletion as well as pest infestation and are modulated by the size and species identity of a tree and its neighbors. A more holistic view that accounts for multiple causes of drought-induced tree mortality is required to improve predictions of trends in global forest dynamics and to identify mutually beneficial species combinations.
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Affiliation(s)
- Peter Hajek
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Roman M Link
- Chair of Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Institute of Biological Sciences, Würzburg, Germany
| | - Charles A Nock
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Jürgen Bauhus
- Chair of Silviculture, University of Freiburg, Freiburg, Germany
| | - Tobias Gebauer
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- ETH Zurich, Institute of Terrestrial Ecosystems, Zurich, Switzerland
| | - Kyle Kovach
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Christian Messier
- Center for Forest Research, Université du Québec à Montréal, Montréal, Quebec, Canada
- University of Quebec in Outaouais (UQO), Institut des Sciences de la Forêt Tempérée (ISFORT), Gatineau, Quebec, Canada
| | - Alain Paquette
- Center for Forest Research, Université du Québec à Montréal, Montréal, Quebec, Canada
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
| | | | - Laura Rose
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Bernhard Schuldt
- Chair of Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Institute of Biological Sciences, Würzburg, Germany
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7
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Hajek P, Link RM, Nock CA, Bauhus J, Gebauer T, Gessler A, Kovach K, Messier C, Paquette A, Saurer M, Scherer-Lorenzen M, Rose L, Schuldt B. Mutually inclusive mechanisms of drought-induced tree mortality. GLOBAL CHANGE BIOLOGY 2022; 28:3365-3378. [PMID: 35246895 DOI: 10.1101/2020.12.17.423038] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/16/2021] [Indexed: 05/22/2023]
Abstract
Unprecedented tree dieback across Central Europe caused by recent global change-type drought events highlights the need for a better mechanistic understanding of drought-induced tree mortality. Although numerous physiological risk factors have been identified, the importance of two principal mechanisms, hydraulic failure and carbon starvation, is still debated. It further remains largely unresolved how the local neighborhood composition affects individual mortality risk. We studied 9435 young trees of 12 temperate species planted in a diversity experiment in 2013 to assess how hydraulic traits, carbon dynamics, pest infestation, tree height and neighborhood competition influence individual mortality risk. Following the most extreme global change-type drought since record in 2018, one third of these trees died. Across species, hydraulic safety margins (HSMs) were negatively and a shift towards a higher sugar fraction in the non-structural carbohydrate (NSC) pool positively associated with mortality risk. Moreover, trees infested by bark beetles had a higher mortality risk, and taller trees a lower mortality risk. Most neighborhood interactions were beneficial, although neighborhood effects were highly species-specific. Species that suffered more from drought, especially Larix spp. and Betula spp., tended to increase the survival probability of their neighbors and vice versa. While severe tissue dehydration marks the final stage of drought-induced tree mortality, we show that hydraulic failure is interrelated with a series of other, mutually inclusive processes. These include shifts in NSC pools driven by osmotic adjustment and/or starch depletion as well as pest infestation and are modulated by the size and species identity of a tree and its neighbors. A more holistic view that accounts for multiple causes of drought-induced tree mortality is required to improve predictions of trends in global forest dynamics and to identify mutually beneficial species combinations.
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Affiliation(s)
- Peter Hajek
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Roman M Link
- Chair of Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Institute of Biological Sciences, Würzburg, Germany
| | - Charles A Nock
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Jürgen Bauhus
- Chair of Silviculture, University of Freiburg, Freiburg, Germany
| | - Tobias Gebauer
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- ETH Zurich, Institute of Terrestrial Ecosystems, Zurich, Switzerland
| | - Kyle Kovach
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Christian Messier
- Center for Forest Research, Université du Québec à Montréal, Montréal, Quebec, Canada
- University of Quebec in Outaouais (UQO), Institut des Sciences de la Forêt Tempérée (ISFORT), Gatineau, Quebec, Canada
| | - Alain Paquette
- Center for Forest Research, Université du Québec à Montréal, Montréal, Quebec, Canada
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
| | | | - Laura Rose
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Bernhard Schuldt
- Chair of Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Institute of Biological Sciences, Würzburg, Germany
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8
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Schreel JDM, Brodersen C, De Schryver T, Dierick M, Rubinstein A, Dewettinck K, Boone MN, Van Hoorebeke L, Steppe K. Foliar water uptake does not contribute to embolism repair in beech (Fagus sylvatica L.). ANNALS OF BOTANY 2022; 129:555-566. [PMID: 35141741 PMCID: PMC9007097 DOI: 10.1093/aob/mcac016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/02/2022] [Indexed: 05/21/2023]
Abstract
BACKGROUND AND AIMS Foliar water uptake has recently been suggested as a possible mechanism for the restoration of hydraulically dysfunctional xylem vessels. In this paper we used a combination of ecophysiological measurements, X-ray microcomputed tomography and cryo-scanning electron microscopy during a drought treatment to fully evaluate this hypothesis. KEY RESULTS Based on an assessment of these methods in beech (Fagus sylvatica L.) seedlings we were able to (1) confirm an increase in the amount of hydraulically redistributed water absorbed by leaves when the soil water potential decreased, and (2) locate this redistributed water in hydraulically active vessels in the stem. However, (3) no embolism repair was observed irrespective of the organ under investigation (i.e. stem, petiole or leaf) or the intensity of drought. CONCLUSIONS Our data provide evidence for a hydraulic pathway from the leaf surface to the stem xylem following a water potential gradient, but this pathway exists only in functional vessels and does not play a role in embolism repair for beech.
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Affiliation(s)
- Jeroen D M Schreel
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
- Institute of Environment, Department of Biological Sciences, Florida International University, Miami, FL, USA
- For correspondence. E-mail
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT, USA
| | - Thomas De Schryver
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Manuel Dierick
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | | | - Koen Dewettinck
- Food Structure & Function Research Group, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
| | - Matthieu N Boone
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Luc Van Hoorebeke
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
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Li X, Xi B, Wu X, Choat B, Feng J, Jiang M, Tissue D. Unlocking Drought-Induced Tree Mortality: Physiological Mechanisms to Modeling. FRONTIERS IN PLANT SCIENCE 2022; 13:835921. [PMID: 35444681 PMCID: PMC9015645 DOI: 10.3389/fpls.2022.835921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Drought-related tree mortality has become a major concern worldwide due to its pronounced negative impacts on the functioning and sustainability of forest ecosystems. However, our ability to identify the species that are most vulnerable to drought, and to pinpoint the spatial and temporal patterns of mortality events, is still limited. Model is useful tools to capture the dynamics of vegetation at spatiotemporal scales, yet contemporary land surface models (LSMs) are often incapable of predicting the response of vegetation to environmental perturbations with sufficient accuracy, especially under stressful conditions such as drought. Significant progress has been made regarding the physiological mechanisms underpinning plant drought response in the past decade, and plant hydraulic dysfunction has emerged as a key determinant for tree death due to water shortage. The identification of pivotal physiological events and relevant plant traits may facilitate forecasting tree mortality through a mechanistic approach, with improved precision. In this review, we (1) summarize current understanding of physiological mechanisms leading to tree death, (2) describe the functionality of key hydraulic traits that are involved in the process of hydraulic dysfunction, and (3) outline their roles in improving the representation of hydraulic function in LSMs. We urge potential future research on detailed hydraulic processes under drought, pinpointing corresponding functional traits, as well as understanding traits variation across and within species, for a better representation of drought-induced tree mortality in models.
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Affiliation(s)
- Ximeng Li
- College of Life and Environmental Science, Minzu University of China, Beijing, China
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Benye Xi
- Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing, China
| | - Xiuchen Wu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Jinchao Feng
- College of Life and Environmental Science, Minzu University of China, Beijing, China
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - David Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Global Centre for Land-based Innovation, Western Sydney University, Richmond, NSW, Australia
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10
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Gauthey A, Peters JMR, Lòpez R, Carins-Murphy MR, Rodriguez-Dominguez CM, Tissue DT, Medlyn BE, Brodribb TJ, Choat B. Mechanisms of xylem hydraulic recovery after drought in Eucalyptus saligna. PLANT, CELL & ENVIRONMENT 2022; 45:1216-1228. [PMID: 35119114 DOI: 10.1111/pce.14265] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
The mechanisms by which woody plants recover xylem hydraulic capacity after drought stress are not well understood, particularly with regard to the role of embolism refilling. We evaluated the recovery of xylem hydraulic capacity in young Eucalyptus saligna plants exposed to cycles of drought stress and rewatering. Plants were exposed to moderate and severe drought stress treatments, with recovery monitored at time intervals from 24 h to 6 months after rewatering. The percentage loss of xylem vessels due to embolism (PLV) was quantified at each time point using microcomputed tomography with stem water potential (Ψx ) and canopy transpiration (Ec ) measured before scans. Plants exposed to severe drought stress suffered high levels of embolism (47.38% ± 10.97% PLV) and almost complete canopy loss. No evidence of embolism refilling was observed at 24 h, 1 week, or 3 weeks after rewatering despite rapid recovery in Ψx . Recovery of hydraulic capacity was achieved over a 6-month period by growth of new xylem tissue, with canopy leaf area and Ec recovering over the same period. These findings indicate that E. saligna recovers slowly from severe drought stress, with potential for embolism to persist in the xylem for many months after rainfall events.
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Affiliation(s)
- Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Jennifer M R Peters
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
- Environmental Sciences Division, Oak Ridge National Laboratory, Climate Change Science Institute, Oak Ridge, Tennessee, USA
| | - Rosana Lòpez
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
- Departamento de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain
| | | | - Celia M Rodriguez-Dominguez
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Sevilla, Spain
- Laboratory of Plant Molecular Ecophysiology, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Sevilla, Spain
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
- Global Centre for Land Based Innovation, Western Syndey University, Richmond, New South Wales, Australia
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Tim J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
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11
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X-ray computed tomography, electron microscopy, and energy-dispersive X-ray spectroscopy of severed Zelkova serrata roots (Japanese elm tree). Micron 2022; 156:103231. [DOI: 10.1016/j.micron.2022.103231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 11/23/2022]
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12
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Dewar R, Hölttä T, Salmon Y. Exploring optimal stomatal control under alternative hypotheses for the regulation of plant sources and sinks. THE NEW PHYTOLOGIST 2022; 233:639-654. [PMID: 34637543 DOI: 10.1111/nph.17795] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Abstract
Experimental evidence that nonstomatal limitations to photosynthesis (NSLs) correlate with leaf sugar and/or leaf water status suggests the possibility that stomata adjust to maximise photosynthesis through a trade-off between leaf CO2 supply and NSLs, potentially involving source-sink interactions. However, the mechanisms regulating NSLs and sink strength, as well as their implications for stomatal control, remain uncertain. We used an analytically solvable model to explore optimal stomatal control under alternative hypotheses for source and sink regulation. We assumed that either leaf sugar concentration or leaf water potential regulates NSLs, and that either phloem turgor pressure or phloem sugar concentration regulates sink phloem unloading. All hypotheses led to realistic stomatal responses to light, CO2 and air humidity, including conservative behaviour for the intercellular-to-atmospheric CO2 concentration ratio. Sugar-regulated and water-regulated NSLs are distinguished by the presence/absence of a stomatal closure response to changing sink strength. Turgor-regulated and sugar-regulated phloem unloading are distinguished by the presence/absence of stomatal closure under drought and avoidance/occurrence of negative phloem turgor. Results from girdling and drought experiments on Pinus sylvestris, Betula pendula, Populus tremula and Picea abies saplings are consistent with optimal stomatal control under sugar-regulated NSLs and turgor-regulated unloading. Our analytical results provide a simple representation of stomatal responses to above-ground and below-ground environmental factors and sink activity.
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Affiliation(s)
- Roderick Dewar
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Teemu Hölttä
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, PO Box 27, Latokartanonkaari 7, Helsinki, 00014, Finland
| | - Yann Salmon
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, PO Box 27, Latokartanonkaari 7, Helsinki, 00014, Finland
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13
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Saluja M, Zhu F, Yu H, Walia H, Sattler SE. Loss of COMT activity reduces lateral root formation and alters the response to water limitation in sorghum brown midrib (bmr) 12 mutant. THE NEW PHYTOLOGIST 2021; 229:2780-2794. [PMID: 33124063 DOI: 10.1111/nph.17051] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
Lignin is a key target for modifying lignocellulosic biomass for efficient biofuel production. Brown midrib 12 (bmr12) encodes the sorghum caffeic acid O-methyltransferase (COMT) and is one of the key enzymes in monolignol biosynthesis. Loss of function mutations in COMT reduces syringyl (S) lignin subunits and improves biofuel conversion rate. Although lignin plays an important role in maintaining cell wall integrity of xylem vessels, physiological and molecular consequences due to loss of COMT on root growth and adaptation to water deficit remain unexplored. We addressed this gap by evaluating the root morphology, anatomy and transcriptome of bmr12 mutant. The mutant had reduced lateral root density (LRD) and altered root anatomy and response to water limitation. The wild-type exhibits similar phenotypes under water stress, suggesting that bmr12 may be in a water deficit responsive state even in well-watered conditions. bmr12 had increased transcript abundance of genes involved in (a)biotic stress response, gibberellic acid (GA) biosynthesis and signaling. We show that bmr12 is more sensitive to exogenous GA application and present evidence for the role of GA in regulating reduced LRD in bmr12. These findings elucidate the phenotypic and molecular consequences of COMT deficiency under optimal and water stress environments in grasses.
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Affiliation(s)
- Manny Saluja
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Feiyu Zhu
- Computer Science and Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Hongfeng Yu
- Computer Science and Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Harkamal Walia
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Scott E Sattler
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
- Wheat, Sorghum and Forage Research Unit, USDA-ARS, Lincoln, NE, 68583, USA
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14
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Secchi F, Pagliarani C, Cavalletto S, Petruzzellis F, Tonel G, Savi T, Tromba G, Obertino MM, Lovisolo C, Nardini A, Zwieniecki MA. Chemical inhibition of xylem cellular activity impedes the removal of drought-induced embolisms in poplar stems - new insights from micro-CT analysis. THE NEW PHYTOLOGIST 2021; 229:820-830. [PMID: 32890423 DOI: 10.1111/nph.16912] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
In drought-stressed plants a coordinated cascade of chemical and transcriptional adjustments occurs at the same time as embolism formation. While these processes do not affect embolism formation during stress, they may prime stems for recovery during rehydration by modifying apoplast pH and increasing sugar concentration in the xylem sap. Here we show that in vivo treatments modifying apoplastic pH (stem infiltration with a pH buffer) or reducing stem metabolic activity (infiltration with sodium vanadate and sodium cyanide; plant exposure to carbon monoxide) can reduce sugar accumulation, thus disrupting or delaying the recovery process. Application of the vanadate treatment (NaVO3, an inhibitor of many ATPases) completely halted recovery from drought-induced embolism for up to 24 h after re-irrigation, while partial recovery was observed in vivo in control plants using X-ray microcomputed tomography. Our results suggest that stem hydraulic recovery in poplar is a biological, energy-dependent process that coincides with accumulation of sugars in the apoplast during stress. Recovery and damage are spatially coordinated, with embolism formation occurring from the inside out and refilling from the outside in. The outside-in pattern highlights the importance of xylem proximity to the sugars within the phloem to the embolism recovery process.
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Affiliation(s)
- Francesca Secchi
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Chiara Pagliarani
- Institute for Sustainable Plant Protection, National Research Council, Strada delle Cacce 73, Torino, 10135, Italy
| | - Silvia Cavalletto
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Francesco Petruzzellis
- Dipartimento di Scienze della Vita, University of Trieste, via Giorgieri 10, Trieste, 34127, Italy
| | - Giulia Tonel
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Tadeja Savi
- Institute of Botany, Department of Integrative Biology and Biodiversity Research, BOKU, Gregor-Mendel-Straße 33, Vienna, 1180, Austria
| | - Giuliana Tromba
- Elettra-Sincrotrone Trieste, Area Science Park, Basovizza, Trieste, 34149, Italy
| | - Maria Margherita Obertino
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Claudio Lovisolo
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, University of Trieste, via Giorgieri 10, Trieste, 34127, Italy
| | - Maciej A Zwieniecki
- Department of Plant Sciences, University of California Davis, One Shields Avenue, Davis, CA, 95616, USA
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15
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Peters JMR, Gauthey A, Lopez R, Carins-Murphy MR, Brodribb TJ, Choat B. Non-invasive imaging reveals convergence in root and stem vulnerability to cavitation across five tree species. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6623-6637. [PMID: 32822502 PMCID: PMC7586747 DOI: 10.1093/jxb/eraa381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 08/18/2020] [Indexed: 05/08/2023]
Abstract
Root vulnerability to cavitation is challenging to measure and under-represented in current datasets. This gap limits the precision of models used to predict plant responses to drought because roots comprise the critical interface between plant and soil. In this study, we measured vulnerability to drought-induced cavitation in woody roots and stems of five tree species (Acacia aneura, Cedrus deodara, Eucalyptus crebra, Eucalytus saligna, and Quercus palustris) with a wide range of xylem anatomies. X-ray microtomography was used to visualize the accumulation of xylem embolism in stems and roots of intact plants that were naturally dehydrated to varying levels of water stress. Vulnerability to cavitation, defined as the water potential causing a 50% loss of hydraulic function (P50), varied broadly among the species (-4.51 MPa to -11.93 MPa in stems and -3.13 MPa to -9.64 MPa in roots). The P50 of roots and stems was significantly related across species, with species that had more vulnerable stems also having more vulnerable roots. While there was strong convergence in root and stem vulnerability to cavitation, the P50 of roots was significantly higher than the P50 of stems in three species. However, the difference in root and stem vulnerability for these species was small; between 1% and 31% of stem P50. Thus, while some differences existed between organs, roots were not dramatically more vulnerable to embolism than stems, and the differences observed were less than those reported in previous studies. Further study is required to evaluate the vulnerability across root orders and to extend these conclusions to a greater number of species and xylem functional types.
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Affiliation(s)
- Jennifer M R Peters
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Oak Ridge National Laboratory, Climate Change Science Institute & Environmental Science Division, Oak Ridge, TN, USA
| | - Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Rosana Lopez
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Departamento de Sistemas y Recursos Naturales. Universidad Politécnica de Madrid, Ciudad Universitaria, Madrid, Spain
| | | | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, TAS, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
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16
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Chen Z, Zhu S, Zhang Y, Luan J, Li S, Sun P, Wan X, Liu S. Tradeoff between storage capacity and embolism resistance in the xylem of temperate broadleaf tree species. TREE PHYSIOLOGY 2020; 40:1029-1042. [PMID: 32310276 DOI: 10.1093/treephys/tpaa046] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Xylem traits are critical plant functional traits associated with water transport, mechanical support, and carbohydrate and water storage. Studies on the xylem hydraulic efficiency-safety tradeoff are numerous; however, the storage function of xylem parenchyma is rarely considered. The effects of a substantial number of xylem traits on water transport, embolism resistance, mechanical support, storage capacity and nonstructural carbohydrate (NSC) content were investigated in 19 temperate broadleaf species planted in an arid limestone habitat in northern China. There was no xylem hydraulic efficiency-safety tradeoff in the 19 broadleaf species. The total parenchyma fraction was negatively correlated with the fiber fraction. Embolism resistance was positively correlated with indicators of xylem mechanical strength such as vessel wall reinforcement, vessel wall thickness and fiber wall thickness, and was negatively related to the axial parenchyma fraction, especially the paratracheal parenchyma fraction. The paratracheal parenchyma fraction was positively correlated with the ratio of the paratracheal parenchyma fraction to the vessel fraction. In addition, the xylem NSC concentration was positively related to the total parenchyma fraction and axial parenchyma fraction. There was a storage capacity-embolism resistance tradeoff in the xylem of 19 broadleaf species in arid limestone habitats. We speculate that the temperate broadleaf species may show a spectrum of xylem hydraulic strategies, from the embolism resistance strategy related to a more negative P50 (the water potential corresponding to 50% loss of xylem conductivity) to the embolization repair strategy based on more paratracheal parenchyma.
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Affiliation(s)
- Zhicheng Chen
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
| | - Yongtao Zhang
- Mountain Tai Forest Ecosystem Research Station of National Forestry and Grassland Administration, Forestry College of Shandong Agricultural University, Taian 271018, China
| | - Junwei Luan
- Key Laboratory of Bamboo and Rattan Science and Technology, Institute for Resources and Environment, International Centre for Bamboo and Rattan, National Forestry and Grassland Administration, Beijing 100102, China
| | - Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
| | - Pengsen Sun
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
| | - Xianchong Wan
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Shirong Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
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17
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Brunetti C, Savi T, Nardini A, Loreto F, Gori A, Centritto M. Changes in abscisic acid content during and after drought are related to carbohydrate mobilization and hydraulic recovery in poplar stems. TREE PHYSIOLOGY 2020; 40:1043-1057. [PMID: 32186735 DOI: 10.1093/treephys/tpaa032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 02/26/2020] [Accepted: 03/13/2020] [Indexed: 06/10/2023]
Abstract
Drought compromises plant's ability to replace transpired water vapor with water absorbed from the soil, leading to extensive xylem dysfunction and causing plant desiccation and death. Short-term plant responses to drought rely on stomatal closure, and on the plant's ability to recover hydraulic functioning after drought relief. We hypothesize a key role for abscisic acid (ABA) not only in the control of stomatal aperture, but also in hydraulic recovery. Young plants of Populus nigra L. were used to investigate possible relationships among ABA, non-structural carbohydrates (NSC) and xylem hydraulic function under drought and after re-watering. In Populus nigra L. plants subjected to drought, water transport efficiency and hydraulic recovery after re-watering were monitored by measuring the percentage loss of hydraulic conductivity (PLC) and stem specific hydraulic conductivity (Kstem). In the same plants ABA and NSC were quantified in wood and bark. Drought severely reduced stomatal conductance (gL) and markedly increased the PLC. Leaf and stem water potential, and stem hydraulic efficiency fully recovered within 24 h after re-watering, but gL values remained low. After re-watering, we found significant correlations between changes in ABA content and hexoses concentration both in wood and bark. Our findings suggest a role for ABA in the regulation of stem carbohydrate metabolism and starch mobilization upon drought relief, possibly promoting the restoration of xylem transport capacity.
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Affiliation(s)
- Cecilia Brunetti
- National Research Council of Italy, Institute for Sustainable Plant Protection, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Florence), Italy
| | - Tadeja Savi
- University of Natural Resources and Life Sciences, Institute of Botany, Department of Integrative Biology and Biodiversity Research, BOKU, Gregor-Mendel-Straße 33, 1190, Vienna, Austria Austria
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Francesco Loreto
- National Research Council of Italy, Department of Biology, Agriculture and Food Sciences, Piazzale Aldo Moro 7, 00185 Roma, Italy
| | - Antonella Gori
- Department of Agri-Food Production and Environmental Sciences, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino (Florence), Italy
| | - Mauro Centritto
- National Research Council of Italy, Institute for Sustainable Plant Protection, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Florence), Italy
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18
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Lamarque LJ, Delzon S, Toups H, Gravel AI, Corso D, Badel E, Burlett R, Charrier G, Cochard H, Jansen S, King A, Torres-Ruiz JM, Pouzoulet J, Cramer GR, Thompson AJ, Gambetta GA. Over-accumulation of abscisic acid in transgenic tomato plants increases the risk of hydraulic failure. PLANT, CELL & ENVIRONMENT 2020; 43:548-562. [PMID: 31850535 DOI: 10.1111/pce.13703] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/11/2019] [Accepted: 12/03/2019] [Indexed: 05/27/2023]
Abstract
Climate change threatens food security, and plant science researchers have investigated methods of sustaining crop yield under drought. One approach has been to overproduce abscisic acid (ABA) to enhance water use efficiency. However, the concomitant effects of ABA overproduction on plant vascular system functioning are critical as it influences vulnerability to xylem hydraulic failure. We investigated these effects by comparing physiological and hydraulic responses to water deficit between a tomato (Solanum lycopersicum) wild type control (WT) and a transgenic line overproducing ABA (sp12). Under well-watered conditions, the sp12 line displayed similar growth rate and greater water use efficiency by operating at lower maximum stomatal conductance. X-ray microtomography revealed that sp12 was significantly more vulnerable to xylem embolism, resulting in a reduced hydraulic safety margin. We also observed a significant ontogenic effect on vulnerability to xylem embolism for both WT and sp12. This study demonstrates that the greater water use efficiency in the tomato ABA overproducing line is associated with higher vulnerability of the vascular system to embolism and a higher risk of hydraulic failure. Integrating hydraulic traits into breeding programmes represents a critical step for effectively managing a crop's ability to maintain hydraulic conductivity and productivity under water deficit.
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Affiliation(s)
- Laurent J Lamarque
- BIOGECO, INRA, Univ. Bordeaux, Pessac, France
- EGFV, Bordeaux-Sciences Agro, INRA, Univ. Bordeaux, ISVV, Villenave d'Ornon, France
| | | | - Haley Toups
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada
| | | | | | - Eric Badel
- INRA, PIAF, Université Clermont-Auvergne, Clermont-Ferrand, France
| | | | | | - Hervé Cochard
- INRA, PIAF, Université Clermont-Auvergne, Clermont-Ferrand, France
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - Andrew King
- Synchrotron SOLEIL, Gif-sur-Yvette Cedex, France
| | | | - Jérôme Pouzoulet
- EGFV, Bordeaux-Sciences Agro, INRA, Univ. Bordeaux, ISVV, Villenave d'Ornon, France
| | - Grant R Cramer
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada
| | - Andrew J Thompson
- Cranfield Soil an Agrifood Institute, Cranfield University, Bedfordshire, UK
| | - Gregory A Gambetta
- EGFV, Bordeaux-Sciences Agro, INRA, Univ. Bordeaux, ISVV, Villenave d'Ornon, France
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19
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Berry ZC, Espejel X, Williams-Linera G, Asbjornsen H. Linking coordinated hydraulic traits to drought and recovery responses in a tropical montane cloud forest. AMERICAN JOURNAL OF BOTANY 2019; 106:1316-1326. [PMID: 31518000 DOI: 10.1002/ajb2.1356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Understanding plant hydraulic functioning and water balance during drought has become key in predicting species survival and recovery. However, there are few insightful studies that couple physiological and morphological attributes for many ecosystems, such as the vulnerable Tropical Montane Cloud Forests (TMCF). In this study, we evaluated drought resistance and recovery for saplings for five tree species spanning deciduous to evergreen habits from a Mexican TMCF. METHODS In drought simulations, water was withheld until plants reached species-specific P50 or P88 values (pressures required to induce a 50 or 88% loss in hydraulic conductivity), then they were rewatered. Drought resistance was considered within the isohydric-anisohydric framework and compared to leaf gas exchange, water status, pressure-volume curves, specific leaf area, and stomatal density. RESULTS The TMCF species closed stomata well before significant losses in hydraulic conductivity (isohydric). Yet, despite the coordination of these traits, the traits were not useful for predicting the time needed for the species to reach critical hydraulic thresholds. Instead, maximum photosynthetic rates explained these times, reinforcing the linkage between hydraulic and carbon dynamics. Despite their varying hydraulic conductivities, stomatal responses, and times to hydraulic thresholds, 58 of the 60 study plants recovered after the rewatering. The recovery of photosynthesis and stomatal conductance can be explained by the P50 values and isohydry. CONCLUSIONS This study raises new questions surrounding drought management strategies, recovery processes, and how lethal thresholds are defined. Further studies need to consider the role of water and carbon balance in allowing for both survival and recovery from drought.
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Affiliation(s)
- Z Carter Berry
- Schmid College of Science and Technology, Chapman University, Orange, CA, 92866, USA
| | - Ximena Espejel
- Instituto de Ecología, A.C., Carretera Antigua a Coatepec 351, Xalapa, Veracruz, 91070, México
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Kiorapostolou N, Da Sois L, Petruzzellis F, Savi T, Trifilò P, Nardini A, Petit G. Vulnerability to xylem embolism correlates to wood parenchyma fraction in angiosperms but not in gymnosperms. TREE PHYSIOLOGY 2019; 39:1675-1684. [PMID: 31211372 DOI: 10.1093/treephys/tpz068] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/26/2019] [Accepted: 05/17/2019] [Indexed: 05/26/2023]
Abstract
Understanding which structural and functional traits are linked to species' vulnerability to embolism formation (P50) may provide fundamental knowledge on plant strategies to maintain an efficient water transport. We measured P50, wood density (WD), mean conduit area, conduit density, percentage areas occupied by vessels, parenchyma cells (PATOT) and fibers (FA) on branches of angiosperm and gymnosperm species. Moreover, we compiled a dataset of published hydraulic and anatomical data to be compared with our results. Species more vulnerable to embolism had lower WD. In angiosperms, the variability in WD was better explained by PATOT and FA, which were highly correlated. Angiosperms with a higher P50 (less negative) had a higher amount of PATOT and total amount of nonstructural carbohydrates. Instead, in gymnosperms, P50 vs PATOT was not significant. The correlation between PATOT and P50 might have a biological meaning and also suggests that the causality of the commonly observed relationship of WD vs P50 is indirect and dependent on the parenchyma fraction. Our study suggests that angiosperms have a potential active embolism reversal capacity in which parenchyma has an important role, while in gymnosperms this might not be the case.
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Affiliation(s)
- Natasa Kiorapostolou
- Dipartimento Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
| | - Luca Da Sois
- Dipartimento Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
| | - Francesco Petruzzellis
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste 34127, Italy
| | - Tadeja Savi
- Institute for Viticulture and Pomology, Department of Crop Sciences, University of Natural Resources and Life Sciences, Vienna, Konrad Lorenz Straße 24, Tulln, Vienna, 3430, Austria
| | - Patrizia Trifilò
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, Viale Ferdinando Stagno d'Alcontres 31, Messina 98166, Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste 34127, Italy
| | - Giai Petit
- Dipartimento Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
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21
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Li X, Blackman CJ, Peters JMR, Choat B, Rymer PD, Medlyn BE, Tissue DT. More than iso/anisohydry: Hydroscapes integrate plant water use and drought tolerance traits in 10 eucalypt species from contrasting climates. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13320] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Ximeng Li
- 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
| | - Jennifer M. R. Peters
- Hawkesbury Institute for the Environment Western Sydney University Penrith NSW Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment Western Sydney University Penrith NSW Australia
| | - Paul D. Rymer
- Hawkesbury Institute for the Environment Western Sydney University Penrith NSW Australia
| | - Belinda E. Medlyn
- 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
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