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Zhao Y, Xiong L, Yin J, Zha X, Li W, Han Y. Understanding the effects of flash drought on vegetation photosynthesis and potential drivers over China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 931:172926. [PMID: 38697519 DOI: 10.1016/j.scitotenv.2024.172926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/05/2024]
Abstract
Flash droughts characterized by rapid onset and intensification are expected to be a new normal under climate change and potentially affect vegetation photosynthesis and terrestrial carbon sink. However, the effects of flash drought on vegetation photosynthesis and their potential dominant driving factors remain uncertain. Here, we quantify the susceptibility and response magnitude of vegetation photosynthesis to flash drought across different ecosystems (i.e., forest, shrubland, grassland, and cropland) in China based on reanalysis and satellite observations. By employing the extreme gradient boosting model, we also identify the dominant factors that influence these flash drought-photosynthesis relationships. We show that over 51.46 % of ecosystems across China are susceptible to flash drought, and grasslands are substantially suppressed, as reflected in both sensitivity and response magnitude (with median gross primary productivity anomalies of -0.13). We further demonstrate that background climate differences (e.g., mean annual temperature and aridity) predominantly regulate the response variation in forest and shrubland, with hotter/colder or drier ecosystems being more severely suppressed by flash drought. However, in grasslands and croplands, the differential vegetation responses are attributed to the intensity of abnormal hydro-meteorological conditions during flash drought (e.g., vapor pressure deficit (VPD) and temperature anomalies). The effects of flash droughts intensify with increasing VPD and nonmonotonically relate to temperature, with colder or hotter temperatures leading to more severe vegetation loss. Our results identify the vulnerable ecological regions under flash drought and enable a better understanding of vegetation photosynthesis response to climate extremes, which may be useful for developing effective management strategies.
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Affiliation(s)
- Yue Zhao
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, PR China.
| | - Lihua Xiong
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, PR China.
| | - Jiabo Yin
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, PR China.
| | - Xini Zha
- Changjiang Water Resources Protection Institute, Wuhan 430051, PR China; Key Laboratory of Ecological Regulation of Non-point Source Pollution in Lake and Reservoir Water Sources, Changjiang Water Resources Commission, Wuhan 430051, PR China.
| | - Wenbin Li
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, PR China.
| | - Yajing Han
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, PR China.
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2
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Mills C, Bartlett MK, Buckley TN. The poorly-explored stomatal response to temperature at constant evaporative demand. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38602407 DOI: 10.1111/pce.14911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/13/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
Changes in leaf temperature are known to drive stomatal responses, because the leaf-to-air water vapour gradient (Δw) increases with temperature if ambient vapour pressure is held constant, and stomata respond to changes in Δw. However, the direct response of stomata to temperature (DRST; the response when Δw is held constant by adjusting ambient humidity) has been examined far less extensively. Though the meagre available data suggest the response is usually positive, results differ widely and defy broad generalisation. As a result, little is known about the DRST. This review discusses the current state of knowledge about the DRST, including numerous hypothesised biophysical mechanisms, potential implications of the response for plant adaptation, and possible impacts of the DRST on plant-atmosphere carbon and water exchange in a changing climate.
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Affiliation(s)
- Colleen Mills
- Department of Plant Sciences, University of California, Davis, USA
| | - Megan K Bartlett
- Department of Viticulture and Enology, University of California, Davis, USA
| | - Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, USA
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3
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Jin N, Yu X, Dong J, Duan M, Mo Y, Feng L, Bai R, Zhao J, Song J, Dossa GGO, Lu H. Vertical variation in leaf functional traits of Parashorea chinensis with different canopy layers. FRONTIERS IN PLANT SCIENCE 2024; 15:1335524. [PMID: 38348271 PMCID: PMC10859428 DOI: 10.3389/fpls.2024.1335524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/08/2024] [Indexed: 02/15/2024]
Abstract
Introduction Canopy species need to shift their ecological adaptation to improve light and water resources utilization, and the study of intraspecific variations in plant leaf functional traits based at individual scale is of great significance for evaluating plant adaptability to climate change. Methods In this study, we evaluate how leaf functional traits of giant trees relate to spatial niche specialization along a vertical gradient. We sampled the tropical flagship species of Parashorea chinensis around 60 meters tall and divided their crowns into three vertical layers. Fourteen key leaf functional traits including leaf morphology, photosynthetic, hydraulic and chemical physiology were measured at each canopy layer to investigate the intraspecific variation of leaf traits and the interrelationships between different functional traits. Additionally, due to the potential impact of different measurement methods (in-situ and ex-situ branch) on photosynthetic physiological parameters, we also compared the effects of these two gas exchange measurements. Results and discussion In-situ measurements revealed that most leaf functional traits of individual-to-individual P. chinensis varied significantly at different canopy heights. Leaf hydraulic traits such as midday leaf water potential (MWP) and leaf osmotic potential (OP) were insignificantly correlated with leaf photosynthetic physiological traits such as maximal net assimilation rate per mass (A mass). In addition, great discrepancies were found between in-situ and ex-situ measurements of photosynthetic parameters. The ex-situ measurements caused a decrease by 53.63%, 27.86%, and 38.05% in A mass, and a decrease of 50.00%, 19.21%, and 27.90% in light saturation point compared to the in-situ measurements. These findings provided insights into our understanding of the response mechanisms of P. chinensis to micro-habitat in Xishuangbanna tropical seasonal rainforests and the fine scale adaption of different resultant of decoupled traits, which have implications for understanding ecological adaption strategies of P. chinensis under environmental changes.
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Affiliation(s)
- Nan Jin
- School of Ecology and Environment Science, Yunnan University, Kunming, China
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- National Forest Ecosystem Research Station at Xishuangbanna, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- Xishuangbanna Forest Ecosystem Yunnan Field Scientific Observation Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Xiaocheng Yu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- National Forest Ecosystem Research Station at Xishuangbanna, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- Xishuangbanna Forest Ecosystem Yunnan Field Scientific Observation Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Jinlong Dong
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- National Forest Ecosystem Research Station at Xishuangbanna, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- Xishuangbanna Forest Ecosystem Yunnan Field Scientific Observation Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Mengcheng Duan
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Yuxuan Mo
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Leiyun Feng
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- National Forest Ecosystem Research Station at Xishuangbanna, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- Xishuangbanna Forest Ecosystem Yunnan Field Scientific Observation Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Rong Bai
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- National Forest Ecosystem Research Station at Xishuangbanna, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- Xishuangbanna Forest Ecosystem Yunnan Field Scientific Observation Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Jianli Zhao
- School of Ecology and Environment Science, Yunnan University, Kunming, China
| | - Jia Song
- School of Environmental and Geographical Science, Shanghai Normal University, Shanghai, China
| | - Gbadamassi Gouvide Olawole Dossa
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Huazheng Lu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- National Forest Ecosystem Research Station at Xishuangbanna, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
- Xishuangbanna Forest Ecosystem Yunnan Field Scientific Observation Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
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4
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Preisler Y, Grünzweig JM, Ahiman O, Amer M, Oz I, Feng X, Muller JD, Ruehr N, Rotenberg E, Birami B, Yakir D. Vapour pressure deficit was not a primary limiting factor for gas exchange in an irrigated, mature dryland Aleppo pine forest. PLANT, CELL & ENVIRONMENT 2023; 46:3775-3790. [PMID: 37680062 DOI: 10.1111/pce.14712] [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: 06/29/2022] [Accepted: 08/23/2023] [Indexed: 09/09/2023]
Abstract
Climate change is often associated with increasing vapour pressure deficit (VPD) and changes in soil moisture (SM). While atmospheric and soil drying often co-occur, their differential effects on plant functioning and productivity remain uncertain. We investigated the divergent effects and underlying mechanisms of soil and atmospheric drought based on continuous, in situ measurements of branch gas exchange with automated chambers in a mature semiarid Aleppo pine forest. We investigated the response of control trees exposed to combined soil-atmospheric drought (low SM, high VPD) during the rainless Mediterranean summer and that of trees experimentally unconstrained by soil dryness (high SM; using supplementary dry season water supply) but subjected to atmospheric drought (high VPD). During the seasonal dry period, branch conductance (gbr ), transpiration rate (E) and net photosynthesis (Anet ) decreased in low-SM trees but greatly increased in high-SM trees. The response of E and gbr to the massive rise in VPD (to 7 kPa) was negative in low-SM trees and positive in high-SM trees. These observations were consistent with predictions based on a simple plant hydraulic model showing the importance of plant water potential in the gbr and E response to VPD. These results demonstrate that avoiding drought on the supply side (SM) and relying on plant hydraulic regulation constrains the effects of atmospheric drought (VPD) as a stressor on canopy gas exchange in mature pine trees under field conditions.
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Affiliation(s)
- Yakir Preisler
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - José M Grünzweig
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ori Ahiman
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
- Institute of Soil, Water and Environmental Sciences, ARO Volcani Center, Beit Dagan, Israel
| | - Madi Amer
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
| | - Itai Oz
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Xue Feng
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jonathan D Muller
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
- School for Climate Studies, Stellenbosch University, Stellenbosch, South Africa
| | - Nadine Ruehr
- Institute of Meteorology and Climate Research-Atmospheric Environmental Research (IMK-IFU), KIT-Campus Alpin, Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen, Germany
| | - Eyal Rotenberg
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
| | - Benjamin Birami
- Institute of Meteorology and Climate Research-Atmospheric Environmental Research (IMK-IFU), KIT-Campus Alpin, Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen, Germany
| | - Dan Yakir
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
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5
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Smith-Martin CM, Muscarella R, Hammond WM, Jansen S, Brodribb TJ, Choat B, Johnson DM, Vargas-G G, Uriarte M. Hydraulic variability of tropical forests is largely independent of water availability. Ecol Lett 2023; 26:1829-1839. [PMID: 37807917 DOI: 10.1111/ele.14314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 07/06/2023] [Accepted: 08/08/2023] [Indexed: 10/10/2023]
Abstract
Tropical rainforest woody plants have been thought to have uniformly low resistance to hydraulic failure and to function near the edge of their hydraulic safety margin (HSM), making these ecosystems vulnerable to drought; however, this may not be the case. Using data collected at 30 tropical forest sites for three key traits associated with drought tolerance, we show that site-level hydraulic diversity of leaf turgor loss point, resistance to embolism (P50 ), and HSMs is high across tropical forests and largely independent of water availability. Species with high HSMs (>1 MPa) and low P50 values (< -2 MPa) are common across the wet and dry tropics. This high site-level hydraulic diversity, largely decoupled from water stress, could influence which species are favoured and become dominant under a drying climate. High hydraulic diversity could also make these ecosystems more resilient to variable rainfall regimes.
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Affiliation(s)
- Chris M Smith-Martin
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA
- Department of Ecology Evolution and Environmental Biology, Columbia University, New York City, New York, USA
| | - Robert Muscarella
- Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - William M Hammond
- Agronomy Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - German Vargas-G
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - María Uriarte
- Department of Ecology Evolution and Environmental Biology, Columbia University, New York City, New York, USA
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6
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Abdalla M, Bitterlich M, Jansa J, Püschel D, Ahmed MA. The role of arbuscular mycorrhizal symbiosis in improving plant water status under drought. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4808-4824. [PMID: 37409696 DOI: 10.1093/jxb/erad249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 06/28/2023] [Indexed: 07/07/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) have been presumed to ameliorate crop tolerance to drought. Here, we review the role of AMF in maintaining water supply to plants from drying soils and the underlying biophysical mechanisms. We used a soil-plant hydraulic model to illustrate the impact of several AMF mechanisms on plant responses to edaphic drought. The AMF enhance the soil's capability to transport water and extend the effective root length, thereby attenuating the drop in matric potential at the root surface during soil drying. The synthesized evidence and the corresponding simulations demonstrate that symbiosis with AMF postpones the stress onset limit, which is defined as the disproportionality between transpiration rates and leaf water potentials, during soil drying. The symbiosis can thus help crops survive extended intervals of limited water availability. We also provide our perspective on future research needs and call for reconciling the dynamic changes in soil and root hydraulics in order to better understand the role of AMF in plant water relations in the face of climate changes.
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Affiliation(s)
- Mohanned Abdalla
- Chair of Root-Soil Interaction, School of Life Sciences, Technical University of Munich, Freising, Germany
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Horticulture, Faculty of Agriculture, University of Khartoum, Khartoum North, Sudan
| | - Michael Bitterlich
- Humboldt-Universität zu Berlin, Thaer-Institute, Division Urban Plant Ecophysiology, Berlin, Germany
| | - Jan Jansa
- Laboratory of Fungal Biology, Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - David Püschel
- Department of Mycorrhizal Symbioses, Institute of Botany of the Czech Academy of Sciences, Průhonice, Czech Republic
| | - Mutez A Ahmed
- Chair of Root-Soil Interaction, School of Life Sciences, Technical University of Munich, Freising, Germany
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
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7
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Koehler T, Wankmüller FJP, Sadok W, Carminati A. Transpiration response to soil drying versus increasing vapor pressure deficit in crops: physical and physiological mechanisms and key plant traits. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4789-4807. [PMID: 37354081 PMCID: PMC10474596 DOI: 10.1093/jxb/erad221] [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: 02/09/2023] [Accepted: 06/07/2023] [Indexed: 06/26/2023]
Abstract
The water deficit experienced by crops is a function of atmospheric water demand (vapor pressure deficit) and soil water supply over the whole crop cycle. We summarize typical transpiration response patterns to soil and atmospheric drying and the sensitivity to plant hydraulic traits. We explain the transpiration response patterns using a soil-plant hydraulic framework. In both cases of drying, stomatal closure is triggered by limitations in soil-plant hydraulic conductance. However, traits impacting the transpiration response differ between the two drying processes and act at different time scales. A low plant hydraulic conductance triggers an earlier restriction in transpiration during increasing vapor pressure deficit. During soil drying, the impact of the plant hydraulic conductance is less obvious. It is rather a decrease in the belowground hydraulic conductance (related to soil hydraulic properties and root length density) that is involved in transpiration down-regulation. The transpiration response to increasing vapor pressure deficit has a daily time scale. In the case of soil drying, it acts on a seasonal scale. Varieties that are conservative in water use on a daily scale may not be conservative over longer time scales (e.g. during soil drying). This potential independence of strategies needs to be considered in environment-specific breeding for yield-based drought tolerance.
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Affiliation(s)
- Tina Koehler
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Fabian J P Wankmüller
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
| | - Walid Sadok
- Agronomy and Plant Genetics, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, Twin Cities, MN, USA
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
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8
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Quetin GR, Anderegg LDL, Boving I, Anderegg WRL, Trugman AT. Observed forest trait velocities have not kept pace with hydraulic stress from climate change. GLOBAL CHANGE BIOLOGY 2023; 29:5415-5428. [PMID: 37421154 DOI: 10.1111/gcb.16847] [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: 03/24/2023] [Accepted: 05/25/2023] [Indexed: 07/09/2023]
Abstract
The extent to which future climate change will increase forest stress and the amount to which species and forest ecosystems can acclimate or adapt to increased stress is a major unknown. We used high-resolution maps of hydraulic traits representing the diversity in tree drought tolerance across the United States, a hydraulically enabled tree model, and forest inventory observations of demographic shifts to quantify the ability for within-species acclimation and between-species range shifts to mediate climate stress. We found that forests are likely to experience increases in both acute and chronic hydraulic stress with climate change. Based on current species distributions, regional hydraulic trait diversity was sufficient to buffer against increased stress in 88% of forested areas. However, observed trait velocities in 81% of forested areas are not keeping up with the rate required to ameliorate projected future stress without leaf area acclimation.
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Affiliation(s)
- G R Quetin
- Department of Geography, University of California, Santa Barbara, California, USA
| | - L D L Anderegg
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California, USA
| | - I Boving
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California, USA
| | - W R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - A T Trugman
- Department of Geography, University of California, Santa Barbara, California, USA
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9
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Hernandez-Santana V, Rodriguez-Dominguez CM, Sebastian-Azcona J, Perez-Romero LF, Diaz-Espejo A. Role of hydraulic traits in stomatal regulation of transpiration under different vapour pressure deficits across five Mediterranean tree crops. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4597-4612. [PMID: 37115664 PMCID: PMC10433928 DOI: 10.1093/jxb/erad157] [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: 03/23/2023] [Accepted: 04/27/2023] [Indexed: 06/19/2023]
Abstract
The differential stomatal regulation of transpiration among plant species in response to water deficit is not fully understood, although several hydraulic traits have been reported to influence it. This knowledge gap is partly due to a lack of direct and concomitant experimental data on transpiration, stomatal conductance, and hydraulic traits. We measured sap flux density (Js), stomatal conductance (gs), and different hydraulic traits in five crop species. Our aim was to contribute to establishing the causal relationship between water consumption and its regulation using a hydraulic trait-based approach. The results showed that the species-specific regulation of Js by gs was overall coordinated with the functional hydraulic traits analysed. Particularly relevant was the negative and significant relationship found between the Huber value (Hv) and its functional analogue ratio between maximum Js and gs (Jsmax/gsmax) which can be understood as a compensation to maintain the hydraulic supply to the leaves. The Hv was also significantly related to the slope of the relationship between gs and Js response to vapour pressure deficit and explained most of its variability, adding up to evidence recognizing Hv as a major trait in plant water relations. Thus, a hydraulic basis for regulation of tree water use should be considered.
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Affiliation(s)
- Virginia Hernandez-Santana
- Irrigation and Ecophysiology Group. Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda Reina Mercedes, 41012 Seville, Spain
- Laboratory of Plant Molecular Ecophysiology, Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda Reina Mercedes, 41012 Seville, Spain
| | - Celia M Rodriguez-Dominguez
- Irrigation and Ecophysiology Group. Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda Reina Mercedes, 41012 Seville, Spain
- Laboratory of Plant Molecular Ecophysiology, Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda Reina Mercedes, 41012 Seville, Spain
| | - Jaime Sebastian-Azcona
- Irrigation and Ecophysiology Group. Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda Reina Mercedes, 41012 Seville, Spain
| | - Luis Felipe Perez-Romero
- Escuela Técnica Superior de Ingeniería, Universidad de Huelva, Avenida del Ejercito s/n. 21007 Huelva, Spain
| | - Antonio Diaz-Espejo
- Irrigation and Ecophysiology Group. Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda Reina Mercedes, 41012 Seville, Spain
- Laboratory of Plant Molecular Ecophysiology, Instituto de Recursos Naturales y Agrobiología (IRNAS), Consejo Superior de Investigaciones Científicas (CSIC), Avda Reina Mercedes, 41012 Seville, Spain
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10
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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. THE NEW PHYTOLOGIST 2023. [PMID: 37376720 DOI: 10.1111/nph.19076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [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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11
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Blonder BW, Aparecido LMT, Hultine KR, Lombardozzi D, Michaletz ST, Posch BC, Slot M, Winter K. Plant water use theory should incorporate hypotheses about extreme environments, population ecology, and community ecology. THE NEW PHYTOLOGIST 2023; 238:2271-2283. [PMID: 36751903 DOI: 10.1111/nph.18800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 01/30/2023] [Indexed: 05/19/2023]
Abstract
Plant water use theory has largely been developed within a plant-performance paradigm that conceptualizes water use in terms of value for carbon gain and that sits within a neoclassical economic framework. This theory works very well in many contexts but does not consider other values of water to plants that could impact their fitness. Here, we survey a range of alternative hypotheses for drivers of water use and stomatal regulation. These hypotheses are organized around relevance to extreme environments, population ecology, and community ecology. Most of these hypotheses are not yet empirically tested and some are controversial (e.g. requiring more agency and behavior than is commonly believed possible for plants). Some hypotheses, especially those focused around using water to avoid thermal stress, using water to promote reproduction instead of growth, and using water to hoard it, may be useful to incorporate into theory or to implement in Earth System Models.
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Affiliation(s)
- Benjamin Wong Blonder
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Luiza Maria Teophilo Aparecido
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, 85008, USA
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, 85008, USA
| | - Danica Lombardozzi
- Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO, 80305, USA
| | - Sean T Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Bradley C Posch
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, 85008, USA
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA
| | - Martijn Slot
- Smithsonian Tropical Research Institute, Balboa, Ancón, 0843-03092, Panama
| | - Klaus Winter
- Smithsonian Tropical Research Institute, Balboa, Ancón, 0843-03092, Panama
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12
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Zhang Y, Fang J, Smith WK, Wang X, Gentine P, Scott RL, Migliavacca M, Jeong S, Litvak M, Zhou S. Satellite solar-induced chlorophyll fluorescence tracks physiological drought stress development during 2020 southwest US drought. GLOBAL CHANGE BIOLOGY 2023; 29:3395-3408. [PMID: 36929655 DOI: 10.1111/gcb.16683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 03/13/2023] [Indexed: 05/16/2023]
Abstract
Monitoring and estimating drought impact on plant physiological processes over large regions remains a major challenge for remote sensing and land surface modeling, with important implications for understanding plant mortality mechanisms and predicting the climate change impact on terrestrial carbon and water cycles. The Orbiting Carbon Observatory 3 (OCO-3), with its unique diurnal observing capability, offers a new opportunity to track drought stress on plant physiology. Using radiative transfer and machine learning modeling, we derive a metric of afternoon photosynthetic depression from OCO-3 solar-induced chlorophyll fluorescence (SIF) as an indicator of plant physiological drought stress. This unique diurnal signal enables a spatially explicit mapping of plants' physiological response to drought. Using OCO-3 observations, we detect a widespread increasing drought stress during the 2020 southwest US drought. Although the physiological drought stress is largely related to the vapor pressure deficit (VPD), our results suggest that plants' sensitivity to VPD increases as the drought intensifies and VPD sensitivity develops differently for shrublands and grasslands. Our findings highlight the potential of using diurnal satellite SIF observations to advance the mechanistic understanding of drought impact on terrestrial ecosystems and to improve land surface modeling.
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Affiliation(s)
- Yao Zhang
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China
- Institute of Carbon Neutrality, Peking University, Beijing, China
| | - Jianing Fang
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China
- Department of Earth and Environmental Engineering, Columbia University, New York, New York, USA
| | - William Kolby Smith
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, USA
| | - Xian Wang
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, USA
| | - Pierre Gentine
- Department of Earth and Environmental Engineering, Columbia University, New York, New York, USA
| | - Russell L Scott
- Southwest Watershed Research Center, USDA Agricultural Research Service, Tucson, Arizona, USA
| | | | - Sujong Jeong
- Department of Environmental Planning, Graduate School of Environmental Studies, Seoul National University, Seoul, South Korea
| | - Marcy Litvak
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Sha Zhou
- State Key Laboratory of Earth Surface Processes and Resources Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
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13
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Potkay A, Feng X. Do stomata optimize turgor-driven growth? A new framework for integrating stomata response with whole-plant hydraulics and carbon balance. THE NEW PHYTOLOGIST 2023; 238:506-528. [PMID: 36377138 DOI: 10.1111/nph.18620] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/11/2022] [Indexed: 06/16/2023]
Abstract
Every existing optimal stomatal model uses photosynthetic carbon assimilation as a proxy for plant evolutionary fitness. However, assimilation and growth are often decoupled, making assimilation less ideal for representing fitness when optimizing stomatal conductance to water vapor and carbon dioxide. Instead, growth should be considered a closer proxy for fitness. We hypothesize stomata have evolved to maximize turgor-driven growth, instead of assimilation, over entire plants' lifetimes, improving their abilities to compete and reproduce. We develop a stomata model that dynamically maximizes whole-stem growth following principles from turgor-driven growth models. Stomata open to assimilate carbohydrates that supply growth and osmotically generate turgor, while stomata close to prevent losses of turgor and growth due to negative water potentials. In steady state, the growth optimization model captures realistic stomatal, growth, and carbohydrate responses to environmental cues, reconciles conflicting interpretations within existing stomatal optimization theories, and explains patterns of carbohydrate storage and xylem conductance observed during and after drought. Our growth optimization hypothesis introduces a new paradigm for stomatal optimization models, elevates the role of whole-plant carbon use and carbon storage in stomatal functioning, and has the potential to simultaneously predict gross productivity, net productivity, and plant mortality through a single, consistent modeling framework.
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Affiliation(s)
- Aaron Potkay
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
| | - Xue Feng
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
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14
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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. THE NEW PHYTOLOGIST 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] [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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15
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Koehler T, Schaum C, Tung SY, Steiner F, Tyborski N, Wild AJ, Akale A, Pausch J, Lueders T, Wolfrum S, Mueller CW, Vidal A, Vahl WK, Groth J, Eder B, Ahmed MA, Carminati A. Above and belowground traits impacting transpiration decline during soil drying in 48 maize (Zea mays) genotypes. ANNALS OF BOTANY 2023; 131:373-386. [PMID: 36479887 PMCID: PMC9992933 DOI: 10.1093/aob/mcac147] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 11/24/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND AIMS Stomatal regulation allows plants to promptly respond to water stress. However, our understanding of the impact of above and belowground hydraulic traits on stomatal regulation remains incomplete. The objective of this study was to investigate how key plant hydraulic traits impact transpiration of maize during soil drying. We hypothesize that the stomatal response to soil drying is related to a loss in soil hydraulic conductivity at the root-soil interface, which in turn depends on plant hydraulic traits. METHODS We investigate the response of 48 contrasting maize (Zea mays) genotypes to soil drying, utilizing a novel phenotyping facility. In this context, we measure the relationship between leaf water potential, soil water potential, soil water content and transpiration, as well as root, rhizosphere and aboveground plant traits. KEY RESULTS Genotypes differed in their responsiveness to soil drying. The critical soil water potential at which plants started decreasing transpiration was related to a combination of above and belowground traits: genotypes with a higher maximum transpiration and plant hydraulic conductance as well as a smaller root and rhizosphere system closed stomata at less negative soil water potentials. CONCLUSIONS Our results demonstrate the importance of belowground hydraulics for stomatal regulation and hence drought responsiveness during soil drying. Furthermore, this finding supports the hypothesis that stomata start to close when soil hydraulic conductivity drops at the root-soil interface.
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Affiliation(s)
| | - Carolin Schaum
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Shu-Yin Tung
- Institute for Agroecology and Organic Farming, Bavarian State Research Center for Agriculture, Freising, Germany
| | | | - Nicolas Tyborski
- Ecological Microbiology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Andreas J Wild
- Agroecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Asegidew Akale
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Johanna Pausch
- Agroecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Tillmann Lueders
- Ecological Microbiology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Sebastian Wolfrum
- Institute for Agroecology and Organic Farming, Bavarian State Research Center for Agriculture, Freising, Germany
| | - Carsten W Mueller
- Soil Science, Technical University of Munich, Freising, Germany
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Alix Vidal
- Soil Biology Group, Wageningen University & Research, Wageningen, The Netherlands
| | - Wouter K Vahl
- Institute for Crop Science and Plant Breeding, Bavarian State Research Center for Agriculture, Freising, Germany
| | - Jennifer Groth
- Institute for Crop Science and Plant Breeding, Bavarian State Research Center for Agriculture, Freising, Germany
| | - Barbara Eder
- Institute for Crop Science and Plant Breeding, Bavarian State Research Center for Agriculture, Freising, Germany
| | - Mutez A Ahmed
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Land, Air and Water Resources, University of California Davis, Davis, CA, USA
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
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16
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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 & ENVIRONMENT 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] [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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17
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Dubbert M, Couvreur V, Kübert A, Werner C. Plant water uptake modelling: added value of cross-disciplinary approaches. PLANT BIOLOGY (STUTTGART, GERMANY) 2023; 25:32-42. [PMID: 36245305 DOI: 10.1111/plb.13478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
In recent years, research interest in plant water uptake strategies has rapidly increased in many disciplines, such as hydrology, plant ecology and ecophysiology. Quantitative modelling approaches to estimate plant water uptake and spatiotemporal dynamics have significantly advanced through different disciplines across scales. Despite this progress, major limitations, for example, predicting plant water uptake under drought or drought impact at large scales, remain. These are less attributed to limitations in process understanding, but rather to a lack of implementation of cross-disciplinary insights into plant water uptake model structure. The main goal of this review is to highlight how the four dominant model approaches, that is, Feddes approach, hydrodynamic approach, optimality and statistical approaches, can be and have been used to create interdisciplinary hybrid models enabling a holistic system understanding that, among other things, embeds plant water uptake plasticity into a broader conceptual view of soil-plant feedbacks of water, nutrient and carbon cycling, or reflects observed drought responses of plant-soil feedbacks and their dynamics under, that is, drought. Specifically, we provide examples of how integration of Bayesian and hydrodynamic approaches might overcome challenges in interpreting plant water uptake related to different travel and residence times of different plant water sources or trade-offs between root system optimization to forage for water and nutrients during different seasons and phenological stages.
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Affiliation(s)
- M Dubbert
- Isotope Biogeochemistry and Gasfluxes, Leibniz Institute of Agricultural Landscape Research (ZALF), Müncheberg, Germany
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
| | - V Couvreur
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - A Kübert
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
- Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, Helsinki, Finland
| | - C Werner
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
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18
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Feldman AF, Short Gianotti DJ, Dong J, Trigo IF, Salvucci GD, Entekhabi D. Tropical surface temperature response to vegetation cover changes and the role of drylands. GLOBAL CHANGE BIOLOGY 2023; 29:110-125. [PMID: 36169920 PMCID: PMC10092849 DOI: 10.1111/gcb.16455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Vegetation cover creates competing effects on land surface temperature: it typically cools through enhancing energy dissipation and warms via decreasing surface albedo. Global vegetation has been previously found to overall net cool land surfaces with cooling contributions from temperate and tropical vegetation and warming contributions from boreal vegetation. Recent studies suggest that dryland vegetation across the tropics strongly contributes to this global net cooling feedback. However, observation-based vegetation-temperature interaction studies have been limited in the tropics, especially in their widespread drylands. Theoretical considerations also call into question the ability of dryland vegetation to strongly cool the surface under low water availability. Here, we use satellite observations to investigate how tropical vegetation cover influences the surface energy balance. We find that while increased vegetation cover would impart net cooling feedbacks across the tropics, net vegetal cooling effects are subdued in drylands. Using observations, we determine that dryland plants have less ability to cool the surface due to their cooling pathways being reduced by aridity, overall less efficient dissipation of turbulent energy, and their tendency to strongly increase solar radiation absorption. As a result, while proportional greening across the tropics would create an overall biophysical cooling feedback, dryland tropical vegetation reduces the overall tropical surface cooling magnitude by at least 14%, instead of enhancing cooling as suggested by previous global studies.
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Affiliation(s)
- Andrew F. Feldman
- Biospheric Sciences LaboratoryNASA Goddard Space Flight CenterGreenbeltMarylandUSA
- NASA Postdoctoral ProgramNASA Goddard Space Flight CenterGreenbeltMarylandUSA
| | - Daniel J. Short Gianotti
- Department of Civil and Environmental EngineeringMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Jianzhi Dong
- Department of Civil and Environmental EngineeringMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Isabel F. Trigo
- Instituto Português do Mar e da Atmosfera I.P. (IPMA)LisbonPortugal
- Instituto Dom Luiz (IDL)LisbonPortugal
| | - Guido D. Salvucci
- Department of Earth and EnvironmentBoston UniversityBostonMassachusettsUSA
| | - Dara Entekhabi
- Department of Civil and Environmental EngineeringMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
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19
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Ibsen PC, Santiago LS, Shiflett SA, Chandler M, Jenerette GD. Irrigated urban trees exhibit greater functional trait plasticity compared to natural stands. Biol Lett 2023; 19:20220448. [PMID: 36596464 PMCID: PMC9810417 DOI: 10.1098/rsbl.2022.0448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Urbanization creates novel ecosystems comprised of species assemblages and environments with no natural analogue. Moreover, irrigation can alter plant function compared to non-irrigated systems. However, the capacity of irrigation to alter functional trait patterns across multiple species is unknown but may be important for the dynamics of urban ecosystems. We evaluated the hypothesis that urban irrigation influences plasticity in functional traits by measuring carbon-gain and water-use traits of 30 tree species planted in Southern California, USA spanning a coastal-to-desert gradient. Tree species respond to irrigation through increasing the carbon-gain trait relationship of leaf nitrogen per specific leaf area compared to their native habitat. Moreover, most species shift to a water-use strategy of greater water loss through stomata when planted in irrigated desert-like environments compared to coastal environments, implying that irrigated species capitalize on increased water availability to cool their leaves in extreme heat and high evaporative demand conditions. Therefore, irrigated urban environments increase the plasticity of trait responses compared to native ecosystems, allowing for novel response to climatic variation. Our results indicate that trees grown in water-resource-rich urban ecosystems can alter their functional traits plasticity beyond those measured in native ecosystems, which can lead to plant trait dynamics with no natural analogue.
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Affiliation(s)
- Peter C. Ibsen
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, USA,Geosciences and Environmental Change Science Center, United States Geological Survey, Denver, CO 80225, USA
| | - Louis S. Santiago
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, USA
| | - Sheri A. Shiflett
- Department of Environmental Sciences, University of North Carolina Wilmington, Wilmington, NC 28403, USA
| | | | - G. Darrel Jenerette
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, USA
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20
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McDowell NG, Ball M, Bond‐Lamberty B, Kirwan ML, Krauss KW, Megonigal JP, Mencuccini M, Ward ND, Weintraub MN, Bailey V. Processes and mechanisms of coastal woody-plant mortality. GLOBAL CHANGE BIOLOGY 2022; 28:5881-5900. [PMID: 35689431 PMCID: PMC9544010 DOI: 10.1111/gcb.16297] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 05/24/2022] [Indexed: 05/26/2023]
Abstract
Observations of woody plant mortality in coastal ecosystems are globally widespread, but the overarching processes and underlying mechanisms are poorly understood. This knowledge deficiency, combined with rapidly changing water levels, storm surges, atmospheric CO2 , and vapor pressure deficit, creates large predictive uncertainty regarding how coastal ecosystems will respond to global change. Here, we synthesize the literature on the mechanisms that underlie coastal woody-plant mortality, with the goal of producing a testable hypothesis framework. The key emergent mechanisms underlying mortality include hypoxic, osmotic, and ionic-driven reductions in whole-plant hydraulic conductance and photosynthesis that ultimately drive the coupled processes of hydraulic failure and carbon starvation. The relative importance of these processes in driving mortality, their order of progression, and their degree of coupling depends on the characteristics of the anomalous water exposure, on topographic effects, and on taxa-specific variation in traits and trait acclimation. Greater inundation exposure could accelerate mortality globally; however, the interaction of changing inundation exposure with elevated CO2 , drought, and rising vapor pressure deficit could influence mortality likelihood. Models of coastal forests that incorporate the frequency and duration of inundation, the role of climatic drivers, and the processes of hydraulic failure and carbon starvation can yield improved estimates of inundation-induced woody-plant mortality.
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Affiliation(s)
- Nate G. McDowell
- Atmospheric Sciences and Global Change DivisionPacific Northwest National LabRichlandWashingtonUSA
- School of Biological SciencesWashington State UniversityPullmanWashingtonUSA
| | - Marilyn Ball
- Plant Science Division, Research School of BiologyThe Australian National UniversityActonAustralian Capital TerritoryAustralia
| | - Ben Bond‐Lamberty
- Joint Global Change Research Institute, Pacific Northwest National LaboratoryCollege ParkMarylandUSA
| | - Matthew L. Kirwan
- Virginia Institute of Marine Science, William & MaryGloucester PointVirginiaUSA
| | - Ken W. Krauss
- U.S. Geological Survey, Wetland and Aquatic Research CenterLafayetteLouisianaUSA
| | | | - Maurizio Mencuccini
- ICREA, Passeig Lluís Companys 23BarcelonaSpain
- CREAFCampus UAB, BellaterraBarcelonaSpain
| | - Nicholas D. Ward
- Marine and Coastal Research LaboratoryPacific Northwest National LaboratorySequimWashingtonUSA
- School of OceanographyUniversity of WashingtonSeattleWashingtonUSA
| | - Michael N. Weintraub
- Department of Environmental SciencesUniversity of ToledoToledoOhioUSA
- Biological Sciences DivisionPacific Northwest National LaboratoryWashingtonUSA
| | - Vanessa Bailey
- Biological Sciences DivisionPacific Northwest National LaboratoryWashingtonUSA
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21
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Gleason SM, Barnard DM, Green TR, Mackay S, Wang DR, Ainsworth EA, Altenhofen J, Brodribb TJ, Cochard H, Comas LH, Cooper M, Creek D, DeJonge KC, Delzon S, Fritschi FB, Hammer G, Hunter C, Lombardozzi D, Messina CD, Ocheltree T, Stevens BM, Stewart JJ, Vadez V, Wenz J, Wright IJ, Yemoto K, Zhang H. Physiological trait networks enhance understanding of crop growth and water use in contrasting environments. PLANT, CELL & ENVIRONMENT 2022; 45:2554-2572. [PMID: 35735161 DOI: 10.1111/pce.14382] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Plant function arises from a complex network of structural and physiological traits. Explicit representation of these traits, as well as their connections with other biophysical processes, is required to advance our understanding of plant-soil-climate interactions. We used the Terrestrial Regional Ecosystem Exchange Simulator (TREES) to evaluate physiological trait networks in maize. Net primary productivity (NPP) and grain yield were simulated across five contrasting climate scenarios. Simulations achieving high NPP and grain yield in high precipitation environments featured trait networks conferring high water use strategies: deep roots, high stomatal conductance at low water potential ("risky" stomatal regulation), high xylem hydraulic conductivity and high maximal leaf area index. In contrast, high NPP and grain yield was achieved in dry environments with low late-season precipitation via water conserving trait networks: deep roots, high embolism resistance and low stomatal conductance at low leaf water potential ("conservative" stomatal regulation). We suggest that our approach, which allows for the simultaneous evaluation of physiological traits, soil characteristics and their interactions (i.e., networks), has potential to improve our understanding of crop performance in different environments. In contrast, evaluating single traits in isolation of other coordinated traits does not appear to be an effective strategy for predicting plant performance.
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Affiliation(s)
- Sean M Gleason
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
| | - Dave M Barnard
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
| | - Timothy R Green
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
| | - Scott Mackay
- Department of Geography & Department of Environment and Sustainability, University at Buffalo, Buffalo, New York, USA
| | - Diane R Wang
- Department of Agronomy, Purdue University, West Lafayette, Indiana, USA
| | - Elizabeth A Ainsworth
- United States Department of Agriculture, Global Change and Photosynthesis Research Unit, Agricultural Research Service, Urbana, Illinois, USA
| | - Jon Altenhofen
- Northern Colorado Water Conservancy District, Berthoud, Colorado, USA
| | - Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
- Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, The University of Tasmania Node, Hobart, Tasmania, Australia
| | - Hervé Cochard
- Université Clermont Auvergne, INRAE, PIAF, Clermont-Ferrand, France
| | - Louise H Comas
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
| | - Mark Cooper
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland, Australia
- Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, The University of Queensland Node, St. Lucia, Queensland, Australia
| | - Danielle Creek
- Université Clermont Auvergne, INRAE, PIAF, Clermont-Ferrand, France
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Kendall C DeJonge
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
| | - Sylvain Delzon
- Université Bordeaux, INRAE, BIOGECO, Pessac, cedex, France
| | - Felix B Fritschi
- Division of Plant Science and Technology, University of Missouri, Columbia, Missouri, USA
| | - Graeme Hammer
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland, Australia
- Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, The University of Queensland Node, St. Lucia, Queensland, Australia
| | - Cameron Hunter
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Danica Lombardozzi
- National Center for Atmospheric Research (NCAR), Climate & Global Dynamics Lab, Boulder, Colorado, USA
| | - Carlos D Messina
- Department of Horticultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Troy Ocheltree
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, Colorado, USA
| | - Bo Maxwell Stevens
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
| | - Jared J Stewart
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
| | | | - Joshua Wenz
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
| | - Ian J Wright
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
- Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, Western Sydney University Node, Penrith, New South Wales, Australia
| | - Kevin Yemoto
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
| | - Huihui Zhang
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
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22
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Assessing the Vitality Status of Plants: Using the Correlation between Stem Water Content and External Environmental Stress. FORESTS 2022. [DOI: 10.3390/f13081198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Plant vitality is an important indicator of plant health. Previous studies have often assessed plant vitality using related physiological parameters, but few studies have examined the effects of changes in plant vitality on stem water content (StWC), which can be measured online, in real time, and nondestructively using a novel fringing impedance sensor. In the present study, the sensor calibration results showed a linear fitting relationship between the sensor output voltage and StWC, with coefficients reaching 0.96. The coefficients of correlations between StWC and four plant physiological parameters related to plant vitality (net photosynthetic rate, transpiration rate, stomatal conductance, and intercellular carbon dioxide concentration) were more than 0.8, indicating that StWC can be used to characterize plant vitality to a certain extent. A comparison between plants with normal vitality and weakened vitality showed that the self-regulation ability of plants gradually weakened as the plant vitality decreased, the diurnal mean of StWC lowered, and the diurnal range of StWC increased. In conclusion, StWC can be used as a new parameter to assess plant vitality.
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23
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Limousin JM, Roussel A, Rodríguez-Calcerrada J, Torres-Ruiz JM, Moreno M, Garcia de Jalon L, Ourcival JM, Simioni G, Cochard H, Martin-StPaul N. Drought acclimation of Quercus ilex leaves improves tolerance to moderate drought but not resistance to severe water stress. PLANT, CELL & ENVIRONMENT 2022; 45:1967-1984. [PMID: 35394675 DOI: 10.1111/pce.14326] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/12/2022] [Accepted: 03/22/2022] [Indexed: 06/14/2023]
Abstract
Increasing temperature and drought can result in leaf dehydration and defoliation even in drought-adapted tree species such as the Mediterranean evergreen Quercus ilex L. The stomatal regulation of leaf water potential plays a central role in avoiding this phenomenon and is constrained by a suite of leaf traits including hydraulic conductance and vulnerability, hydraulic capacitance, minimum conductance to water vapour, osmotic potential and cell wall elasticity. We investigated whether the plasticity in these traits may improve leaf tolerance to drought in two long-term rainfall exclusion experiments in Mediterranean forests. Osmotic adjustment was observed to lower the water potential at turgor loss in the rainfall-exclusion treatments, thus suggesting a stomatal closure at more negative water potentials and a more anisohydric behaviour in drier conditions. Conversely, leaf hydraulic conductance and vulnerability did not exhibit any plasticity between treatments so the hydraulic safety margins were narrower in the rainfall-exclusion treatments. The sequence of leaf responses to seasonal drought and dehydration was conserved among treatments and sites but trees were more likely to suffer losses of turgor and hydraulic functioning in the rainfall-exclusion treatments. We conclude that leaf plasticity might help the trees to tolerate moderate drought but not to resist severe water stress.
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Affiliation(s)
| | - Amélie Roussel
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Jesús Rodríguez-Calcerrada
- Departamento de Sistemas y Recursos Naturales, ETSI Montes, Forestal y del Medio Natural, Universidad Politécnica de Madrid Ciudad Universitaria, Madrid, Spain
| | | | - Myriam Moreno
- Unité Ecologie des Forêts Méditerranéennes (UR629), INRAE Avignon Cedex 9, Domaine Saint Paul, Site Agroparc, France
| | | | | | - Guillaume Simioni
- Unité Ecologie des Forêts Méditerranéennes (UR629), INRAE Avignon Cedex 9, Domaine Saint Paul, Site Agroparc, France
| | - Hervé Cochard
- PIAF, University Clermont-Auvergne, INRAE, Clermont-Ferrand, France
| | - Nicolas Martin-StPaul
- Unité Ecologie des Forêts Méditerranéennes (UR629), INRAE Avignon Cedex 9, Domaine Saint Paul, Site Agroparc, France
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24
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Disjoining pressure driven transpiration of water in a simulated tree. J Colloid Interface Sci 2022; 616:895-902. [DOI: 10.1016/j.jcis.2022.02.108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 11/23/2022]
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25
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Cai G, Ahmed MA, Abdalla M, Carminati A. Root hydraulic phenotypes impacting water uptake in drying soils. PLANT, CELL & ENVIRONMENT 2022; 45:650-663. [PMID: 35037263 PMCID: PMC9303794 DOI: 10.1111/pce.14259] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 05/11/2023]
Abstract
Soil drying is a limiting factor for crop production worldwide. Yet, it is not clear how soil drying impacts water uptake across different soils, species, and root phenotypes. Here we ask (1) what root phenotypes improve the water use from drying soils? and (2) what root hydraulic properties impact water flow across the soil-plant continuum? The main objective is to propose a hydraulic framework to investigate the interplay between soil and root hydraulic properties on water uptake. We collected highly resolved data on transpiration, leaf and soil water potential across 11 crops and 10 contrasting soil textures. In drying soils, the drop in water potential at the soil-root interface resulted in a rapid decrease in soil hydraulic conductance, especially at higher transpiration rates. The analysis reveals that water uptake was limited by soil within a wide range of soil water potential (-6 to -1000 kPa), depending on both soil textures and root hydraulic phenotypes. We propose that a root phenotype with low root hydraulic conductance, long roots and/or long and dense root hairs postpones soil limitation in drying soils. The consequence of these root phenotypes on crop water use is discussed.
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Affiliation(s)
- Gaochao Cai
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER)University of BayreuthBayreuthGermany
| | - Mutez A. Ahmed
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER)University of BayreuthBayreuthGermany
- Department of Land, Air and Water ResourcesUniversity of California DavisDavisCaliforniaUnited States
| | - Mohanned Abdalla
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER)University of BayreuthBayreuthGermany
| | - Andrea Carminati
- Department of Environmental Systems Science, Physics of Soils and Terrestrial EcosystemsInstitute of Terrestrial Ecosystems, ETH ZürichZurichSwitzerland
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26
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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. GLOBAL CHANGE BIOLOGY 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] [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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27
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Do details matter? Disentangling the processes related to plant species interactions in two grassland models of different complexity. Ecol Modell 2021. [DOI: 10.1016/j.ecolmodel.2021.109737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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28
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Taneda H, Ikeda T. Hydraulic architecture with high root-resistance fraction contributes to efficient carbon gain of plants in temperate habitats. AMERICAN JOURNAL OF BOTANY 2021; 108:1932-1945. [PMID: 34658016 DOI: 10.1002/ajb2.1753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 06/30/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
PREMISE The hydraulic architecture in the leaves, stems and roots of plants constrains water transport and carbon gain through stomatal limitation to CO2 absorption. Because roots are the main bottleneck in water transport for a range of plant species, we assessed the ecophysiological mechanism and importance of a high fraction of root hydraulic resistance in woody and herbaceous species. METHODS Biomass partitioning and hydraulic conductance of leaves, stems, and roots of Japanese knotweed (Fallopia japonica, a perennial herb) and Japanese zelkova (Zelkova serrata, a deciduous tall tree) were measured. Theoretical analyses were used to examine whether the measured hydraulic architecture and biomass partitioning maximized the plant photosynthetic rate (the product of leaf area and photosynthetic rate per leaf area). RESULTS Root hydraulic resistance accounted for 83% and 68% of the total plant resistance for Japanese knotweed and Japanese zelkova, respectively. Comparisons of hydraulic and biomass partitioning revealed that high root-resistance fractions were attributable to low biomass partitioning to root organs rather than high mass-specific root conductance. The measured partitioning of hydraulic resistance closely corresponded to the predicted optimal partitioning, maximizing the plant photosynthetic rate for the two species. The high fraction of root resistance was predicted to be optimal with variations in air humidity and soil water potential. CONCLUSIONS These results suggest that the hydraulic architecture of plants growing in mesic and fertile habitats not only results in high root resistance due to small biomass partitioning to root organs, but contributes to efficient carbon gain.
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Affiliation(s)
- Haruhiko Taneda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, 113-0033, Japan
| | - Takefumi Ikeda
- Department of Forest Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Shimogamohangi-cho, Sakyo, Kyoto, 606-8522, Japan
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29
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Brodribb T, Brodersen CR, Carriqui M, Tonet V, Rodriguez Dominguez C, McAdam S. Linking xylem network failure with leaf tissue death. THE NEW PHYTOLOGIST 2021; 232:68-79. [PMID: 34164816 DOI: 10.1111/nph.17577] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
Global warming is expected to dramatically accelerate forest mortality as temperature and drought intensity increase. Predicting the magnitude of this impact urgently requires an understanding of the process connecting atmospheric drying to plant tissue damage. Recent episodes of forest mortality worldwide have been widely attributed to dry conditions causing acute damage to plant vascular systems. Under this scenario vascular embolisms produced by water stress are thought to cause plant death, yet this hypothetical trajectory has never been empirically demonstrated. Here we provide foundational evidence connecting failure in the vascular network of leaves with tissue damage caused during water stress. We observe a catastrophic sequence initiated by water column breakage under tension in leaf veins which severs local leaf tissue water supply, immediately causing acute cellular dehydration and irreversible damage. By highlighting the primacy of vascular network failure in the death of leaves exposed to drought or evaporative stress our results provide a strong mechanistic foundation upon which models of plant damage in response to dehydration can be confidently structured.
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Affiliation(s)
- Timothy Brodribb
- School of Biological Sciences, University of Tasmania, Sandy Bay, Tasmania, 7001, Australia
| | - Craig R Brodersen
- School of the Environment, Yale University, New Haven, CT, 06511, USA
| | - Marc Carriqui
- School of Biological Sciences, University of Tasmania, Sandy Bay, Tasmania, 7001, Australia
| | - Vanessa Tonet
- School of Biological Sciences, University of Tasmania, Sandy Bay, Tasmania, 7001, Australia
| | - Celia Rodriguez Dominguez
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Avda. Reina Mercedes, 10, Sevilla, 41012, Spain
| | - Scott McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
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30
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Flo V, Martínez-Vilalta J, Mencuccini M, Granda V, Anderegg WRL, Poyatos R. Climate and functional traits jointly mediate tree water-use strategies. THE NEW PHYTOLOGIST 2021; 231:617-630. [PMID: 33893652 DOI: 10.1111/nph.17404] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 04/03/2021] [Indexed: 06/12/2023]
Abstract
Tree water use is central to plant function and ecosystem fluxes. However, it is still unknown how organ-level water-relations traits are coordinated to determine whole-tree water-use strategies in response to drought, and whether this coordination depends on climate. Here we used a global sap flow database (SAPFLUXNET) to study the response of water use, in terms of whole-tree canopy conductance (G), to vapour pressure deficit (VPD) and to soil water content (SWC) for 142 tree species. We investigated the individual and coordinated effect of six water-relations traits (vulnerability to embolism, Huber value, hydraulic conductivity, turgor-loss point, rooting depth and leaf size) on water-use parameters, also accounting for the effect of tree height and climate (mean annual precipitation, MAP). Reference G and its sensitivity to VPD were tightly coordinated with water-relations traits rather than with MAP. Species with efficient xylem transport had higher canopy conductance but also higher sensitivity to VPD. Moreover, we found that angiosperms had higher reference G and higher sensitivity to VPD than did gymnosperms. Our results highlight the need to consider trait integration and reveal the complications and challenges of defining a single, whole-plant resource use spectrum ranging from 'acquisitive' to 'conservative'.
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Affiliation(s)
- Victor Flo
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- Univ Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
| | - Jordi Martínez-Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- Univ Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
| | - Maurizio Mencuccini
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- ICREA, Barcelona, 08010, Spain
| | - Victor Granda
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
| | - William R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Rafael Poyatos
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- Univ Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
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31
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Potkay A, Trugman AT, Wang Y, Venturas MD, Anderegg WRL, Mattos CRC, Fan Y. Coupled whole-tree optimality and xylem hydraulics explain dynamic biomass partitioning. THE NEW PHYTOLOGIST 2021; 230:2226-2245. [PMID: 33521942 DOI: 10.1111/nph.17242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 01/25/2021] [Indexed: 06/12/2023]
Abstract
Trees partition biomass in response to resource limitation and physiological activity. It is presumed that these strategies evolved to optimize some measure of fitness. If the optimization criterion can be specified, then allometry can be modeled from first principles without prescribed parameterization. We present the Tree Hydraulics and Optimal Resource Partitioning (THORP) model, which optimizes allometry by estimating allocation fractions to organs as proportional to their ratio of marginal gain to marginal cost, where gain is net canopy photosynthesis rate, and costs are senescence rates. Root total biomass and profile shape are predicted simultaneously by a unified optimization. Optimal partitioning is solved by a numerically efficient analytical solution. THORP's predictions agree with reported tree biomass partitioning in response to size, water limitations, elevated CO2 and pruning. Roots were sensitive to soil moisture profiles and grew down to the groundwater table when present. Groundwater buffered against water stress regardless of meteorology, stabilizing allometry and root profiles as deep as c. 30 m. Much of plant allometry can be explained by hydraulic considerations. However, nutrient limitations cannot be fully ignored. Rooting mass and profiles were synchronized with hydrological conditions and groundwater even at considerable depths, illustrating that the below ground shapes whole-tree allometry.
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Affiliation(s)
- Aaron Potkay
- Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Anna T Trugman
- Department of Geography, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Yujie Wang
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Martin D Venturas
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - William R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Caio R C Mattos
- Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Ying Fan
- Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ, 08854, USA
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Abdalla M, Carminati A, Cai G, Javaux M, Ahmed MA. Stomatal closure of tomato under drought is driven by an increase in soil-root hydraulic resistance. PLANT, CELL & ENVIRONMENT 2021; 44:425-431. [PMID: 33150971 DOI: 10.1111/pce.13939] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 11/01/2020] [Indexed: 05/14/2023]
Abstract
The fundamental question as to what triggers stomatal closure during soil drying remains contentious. Thus, we urgently need to improve our understanding of stomatal response to water deficits in soil and atmosphere. Here, we investigated the role of soil-plant hydraulic conductance (Ksp ) on transpiration (E) and stomatal regulation. We used a root pressure chamber to measure the relation between E, leaf xylem water potential (ψleaf-x ) and soil water potential (ψsoil ) in tomato. Additional measurements of ψleaf-x were performed with unpressurized plants. A soil-plant hydraulic model was used to simulate E(ψleaf-x ) for decreasing ψsoil . In wet soils, E(ψleaf-x ) had a constant slope, while in dry soils, the slope decreased, with ψleaf-x rapidly and nonlinearly decreasing for moderate increases in E. The ψleaf-x measured in pressurized and unpressurized plants matched well, which indicates that the shoot hydraulic conductance did not decrease during soil drying and that the decrease in Ksp is caused by a decrease in soil-root conductance. The decrease of E matched well the onset of hydraulic nonlinearity. Our findings demonstrate that stomatal closure prevents the drop in ψleaf-x caused by a decrease in Ksp and elucidate a strong correlation between stomatal regulation and belowground hydraulic limitation.
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Affiliation(s)
- Mohanned Abdalla
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Horticulture, Faculty of Agriculture, University of Khartoum, Khartoum North, Sudan
| | - Andrea Carminati
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Gaochao Cai
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Biogeochemistry of Agroecosystems, University of Göttingen, Göttingen, Germany
| | - Mathieu Javaux
- Earth and Life Institute-Environmental Science, Universite Catholique de Louvain, Louvain-la-Neuve, Belgium
- Agrosphere (IBG-3), Forschungszentrum Juelich GmbH, Juelich, Germany
| | - Mutez Ali Ahmed
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Biogeochemistry of Agroecosystems, University of Göttingen, Göttingen, Germany
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33
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Wargowsky IK, NeSmith JE, Holdo RM. Root vascular traits differ systematically between African savanna tree and grass species, with implications for water use. AMERICAN JOURNAL OF BOTANY 2021; 108:83-90. [PMID: 33450049 DOI: 10.1002/ajb2.1597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/17/2020] [Indexed: 06/12/2023]
Abstract
PREMISE Belowground functional traits play a significant role in determining plant water-use strategies and plant performance, but we lack data on root traits across communities, particularly in the tropical savanna biome, where vegetation dynamics are hypothesized to be strongly driven by tree-grass functional differences in water use. METHODS We grew seedlings of 21 tree and 18 grass species (N = 5 individuals per species) from the southern African savanna biome under greenhouse conditions and collected fine-root segments from plants for histological analysis. We identified and measured xylem vessels in 539 individual root cross sections. We then quantified six root vascular anatomy traits and tested them for phylogenetic signals and tree-grass differences in trait values associated with vessel size, number, and hydraulic conductivity. RESULTS Grass roots had larger root xylem vessels than trees, a higher proportion of their root cross-sectional area comprised vessels, and they had higher estimated axial conductivities than trees, while trees had a higher number of vessels per root cross-sectional area than grasses did. We found evidence of associations between trait values and phylogenetic relatedness in most of these traits across tree species, but not grasses. CONCLUSIONS Our findings support the hypothesis that grass roots have higher water transport capacity than tree roots in terms of maximum axial conductivity, consistent with the observation that grasses are more "aggressive" water users than trees under conditions of high soil moisture availability. Our study identifies root functional traits that may drive differential responses of trees and grasses to soil moisture availability.
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Affiliation(s)
| | | | - Ricardo M Holdo
- Odum School of Ecology, University of Georgia, Athens, GA, 30602, USA
- School of Animal Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, 2050, South Africa
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34
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Biomass Dynamics in a Fragment of Brazilian Tropical Forest (Caatinga) over Consecutive Dry Years. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10217813] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Increases in water scarcity due to climate change, especially in dry regions, can affect the dynamics of successional species. In view of the longest sequence of dry years (2010–2019) to have occurred in the Brazilian semi-arid region, with a consequent reduction in water availability, the influence of rainfall distribution on the production of above-ground plant biomass was investigated in a Dry Tropical Forest (DTF). This natural change monitoring experiment was conducted over 11 years (2009–2019) in a fragment of DTF under regeneration for 40 years, in the district of Iguatu, Ceará, Brazil. All living individuals of the woody component with a Diameter at Ground Level (DGL) ≥3 cm and a height (h) ≥100 cm were measured during 2009–2010, 2015–2016, 2018–2019. Biomass production was calculated using an allometric equation defined for DTF species. A mean mortality rate of 134 ind. ha−1 yr−1 was registered, with a recruitment of 39 ind. ha−1 yr−1, generating a mean deficit of 95 ind. ha−1 yr−1. The mean reduction in biomass was 3.26 Mg ha−1 yr−1. Climate conditions during consecutive dry years have a direct effect on the mortality and recruitment of woody species, with a recruitment/mortality ratio of 0.11. Shrubby-tree individuals of smaller diameter showed less resilience to the cumulative effect of drought.
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Gourlez de la Motte L, Beauclaire Q, Heinesch B, Cuntz M, Foltýnová L, Šigut L, Kowalska N, Manca G, Ballarin IG, Vincke C, Roland M, Ibrom A, Lousteau D, Siebicke L, Neiryink J, Longdoz B. Non-stomatal processes reduce gross primary productivity in temperate forest ecosystems during severe edaphic drought. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190527. [PMID: 32892725 DOI: 10.1098/rstb.2019.0527] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Severe drought events are known to cause important reductions of gross primary productivity (GPP) in forest ecosystems. However, it is still unclear whether this reduction originates from stomatal closure (Stomatal Origin Limitation) and/or non-stomatal limitations (Non-SOL). In this study, we investigated the impact of edaphic drought in 2018 on GPP and its origin (SOL, NSOL) using a dataset of 10 European forest ecosystem flux towers. In all stations where GPP reductions were observed during the drought, these were largely explained by declines in the maximum apparent canopy scale carboxylation rate VCMAX,APP (NSOL) when the soil relative extractable water content dropped below around 0.4. Concurrently, we found that the stomatal slope parameter (G1, related to SOL) of the Medlyn et al. unified optimization model linking vegetation conductance and GPP remained relatively constant. These results strengthen the increasing evidence that NSOL should be included in stomatal conductance/photosynthesis models to faithfully simulate both GPP and water fluxes in forest ecosystems during severe drought. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.
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Affiliation(s)
- Louis Gourlez de la Motte
- Terra Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
| | - Quentin Beauclaire
- Terra Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
| | - Bernard Heinesch
- Terra Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
| | - Mathias Cuntz
- Université de Lorraine, AgroParisTech, INRA, UMR Silva, 54000 Nancy, France
| | | | - Ladislav Šigut
- Global Change Research Institute CAS, Brno, Czech Republic
| | | | - Giovanni Manca
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | | - Caroline Vincke
- Earth and Life Institute, UCLouvain, Louvain-la-Neuve, Belgium
| | - Marilyn Roland
- Plants and Ecosystems, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Andreas Ibrom
- Department of Environmental Engineering, Technical University of Denmark (DTU), Bygningstorvet 115, 2800 Lyngby, Denmark
| | | | - Lukas Siebicke
- Bioclimatology, University of Goettingen, Büsgenweg 2, 37077 Goettingen, Germany
| | - Johan Neiryink
- Institute for Nature and Forest Research, INBO, Havenlaan 88 Box 73, 1000 Brussels, Belgium
| | - Bernard Longdoz
- Terra Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
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36
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Carminati A, Javaux M. Soil Rather Than Xylem Vulnerability Controls Stomatal Response to Drought. TRENDS IN PLANT SCIENCE 2020; 25:868-880. [PMID: 32376085 DOI: 10.1016/j.tplants.2020.04.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 03/29/2020] [Accepted: 04/01/2020] [Indexed: 05/12/2023]
Abstract
The current trend towards linking stomata regulation to plant hydraulics emphasizes the role of xylem vulnerability. Using a soil-plant hydraulic model, we show that xylem vulnerability does not trigger stomatal closure in medium-wet to dry soils and we propose that soil hydraulic conductivity loss is the primary driver of stomatal closure. This finding has two key implications: transpiration response to drought cannot be derived from plant traits only and is related to soil-root hydraulics in a predictable way; roots and their interface with the soil, the rhizosphere, are key hydraulic regions that plants can alter to efficiently adapt to water limitations. We conclude that connecting below- and aboveground hydraulics is necessary to fully comprehend plant responses to drought.
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Affiliation(s)
- Andrea Carminati
- University of Bayreuth, Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), Universitätstrasse 30, D-95447 Bayreuth, Germany
| | - Mathieu Javaux
- Université Catholique de Louvain, Earth and Life Institute, Croix du Sud L7.05.02, B-1348 Louvain-la-Neuve, Belgium; Agrosphere, Forschungszentrum Juelich GmbH, D-52425, Juelich, Germany.
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37
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Wang Y, Sperry JS, Anderegg WRL, Venturas MD, Trugman AT. A theoretical and empirical assessment of stomatal optimization modeling. THE NEW PHYTOLOGIST 2020; 227:311-325. [PMID: 32248532 DOI: 10.1111/nph.16572] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/09/2020] [Indexed: 05/13/2023]
Abstract
Optimal stomatal control models have shown great potential in predicting stomatal behavior and improving carbon cycle modeling. Basic stomatal optimality theory posits that stomatal regulation maximizes the carbon gain relative to a penalty of stomatal opening. All models take a similar approach to calculate instantaneous carbon gain from stomatal opening (the gain function). Where the models diverge is in how they calculate the corresponding penalty (the penalty function). In this review, we compare and evaluate 10 different optimization models in how they quantify the penalty and how well they predict stomatal responses to the environment. We evaluate models in two ways. First, we compare their penalty functions against seven criteria that ensure a unique and qualitatively realistic solution. Second, we quantitatively test model against multiple leaf gas-exchange datasets. The optimization models with better predictive skills have penalty functions that meet our seven criteria and use fitting parameters that are both few in number and physiology based. The most skilled models are those with a penalty function based on stress-induced hydraulic failure. We conclude by proposing a new model that has a hydraulics-based penalty function that meets all seven criteria and demonstrates a highly predictive skill against our test datasets.
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Affiliation(s)
- Yujie Wang
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - John S Sperry
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - William R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Martin D Venturas
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Anna T Trugman
- Department of Geography, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
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38
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Powers JS, Vargas G G, Brodribb TJ, Schwartz NB, Pérez-Aviles D, Smith-Martin CM, Becknell JM, Aureli F, Blanco R, Calderón-Morales E, Calvo-Alvarado JC, Calvo-Obando AJ, Chavarría MM, Carvajal-Vanegas D, Jiménez-Rodríguez CD, Murillo Chacon E, Schaffner CM, Werden LK, Xu X, Medvigy D. A catastrophic tropical drought kills hydraulically vulnerable tree species. GLOBAL CHANGE BIOLOGY 2020; 26:3122-3133. [PMID: 32053250 DOI: 10.1111/gcb.15037] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/17/2020] [Accepted: 02/02/2020] [Indexed: 06/10/2023]
Abstract
Drought-related tree mortality is now a widespread phenomenon predicted to increase in magnitude with climate change. However, the patterns of which species and trees are most vulnerable to drought, and the underlying mechanisms have remained elusive, in part due to the lack of relevant data and difficulty of predicting the location of catastrophic drought years in advance. We used long-term demographic records and extensive databases of functional traits and distribution patterns to understand the responses of 20-53 species to an extreme drought in a seasonally dry tropical forest in Costa Rica, which occurred during the 2015 El Niño Southern Oscillation event. Overall, species-specific mortality rates during the drought ranged from 0% to 34%, and varied little as a function of tree size. By contrast, hydraulic safety margins correlated well with probability of mortality among species, while morphological or leaf economics spectrum traits did not. This firmly suggests hydraulic traits as targets for future research.
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Affiliation(s)
- Jennifer S Powers
- Department of Ecology, Evolution, & Behavior, University of Minnesota, St. Paul, MN, USA
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
| | - German Vargas G
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Tas., Australia
| | - Naomi B Schwartz
- Department of Geography, University of British Columbia, Vancouver, BC, Canada
| | - Daniel Pérez-Aviles
- Department of Ecology, Evolution, & Behavior, University of Minnesota, St. Paul, MN, USA
| | - Chris M Smith-Martin
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
| | | | - Filippo Aureli
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
- Instituto de Neuroetologia, Universidad Veracruzana, Xalapa, Mexico
| | - Roger Blanco
- Programa de Investigación, Área de Conservación Guanacaste, Sistema Nacional de Areas de Conservación, Ministerio de Ambiente y Energía, Liberia, Costa Rica
| | - Erick Calderón-Morales
- Department of Ecology, Evolution, & Behavior, University of Minnesota, St. Paul, MN, USA
| | | | | | - María Marta Chavarría
- Programa de Investigación, Área de Conservación Guanacaste, Sistema Nacional de Areas de Conservación, Ministerio de Ambiente y Energía, Liberia, Costa Rica
| | | | - César D Jiménez-Rodríguez
- Escuela de Ingeniería Forestal, Tecnológico de Costa Rica, Cartago, Costa Rica
- Water Resources Section, Delft University of Technology, Delft, The Netherlands
| | - Evin Murillo Chacon
- Programa de Investigación, Área de Conservación Guanacaste, Sistema Nacional de Areas de Conservación, Ministerio de Ambiente y Energía, Liberia, Costa Rica
| | - Colleen M Schaffner
- Instituto de Neuroetologia, Universidad Veracruzana, Xalapa, Mexico
- Psychology Department, Adams State University, Alamosa, CO, USA
| | - Leland K Werden
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
| | - Xiangtao Xu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - David Medvigy
- Department of Biological Science, University of Notre Dame, Notre Dame, IN, USA
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Brodribb TJ, Sussmilch F, McAdam SAM. From reproduction to production, stomata are the master regulators. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:756-767. [PMID: 31596990 DOI: 10.1111/tpj.14561] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/14/2019] [Accepted: 10/03/2019] [Indexed: 05/22/2023]
Abstract
The best predictor of leaf level photosynthetic rate is the porosity of the leaf surface, as determined by the number and aperture of stomata on the leaf. This remarkable correlation between stomatal porosity (or diffusive conductance to water vapour gs ) and CO2 assimilation rate (A) applies to all major lineages of vascular plants (Figure 1) and is sufficiently predictable that it provides the basis for the model most widely used to predict water and CO2 fluxes from leaves and canopies. Yet the Ball-Berry formulation is only a phenomenological approximation that captures the emergent character of stomatal behaviour. Progressing to a more mechanistic prediction of plant gas exchange is challenging because of the diversity of biological components regulating stomatal action. These processes are the product of more than 400 million years of co-evolution between stomatal, vascular and photosynthetic tissues. Both molecular and structural components link the abiotic world of the whole plant with the turgor pressure of the epidermis and guard cells, which ultimately determine stomatal pore size and porosity to water and CO2 exchange (New Phytol., 168, 2005, 275). In this review we seek to simplify stomatal behaviour by using an evolutionary perspective to understand the principal selective pressures involved in stomatal evolution, thus identifying the primary regulators of stomatal aperture. We start by considering the adaptive process that has locked together the regulation of water and carbon fluxes in vascular plants, finally examining specific evidence for evolution in the proteins responsible for regulating guard cell turgor.
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Affiliation(s)
- Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Frances Sussmilch
- Institute for Molecular Plant Physiology and Biophysics, University of Wurzburg, Wuerzburg, Bavaria, Germany
| | - Scott A M McAdam
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
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40
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Ding J, Johnson EA, Martin YE. Optimization of leaf morphology in relation to leaf water status: A theory. Ecol Evol 2020; 10:1510-1525. [PMID: 32076530 PMCID: PMC7029057 DOI: 10.1002/ece3.6004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 12/14/2022] Open
Abstract
The leaf economic traits such as leaf area, maximum carbon assimilation rate, and venation are all correlated and related to water availability. Furthermore, leaves are often broad and large in humid areas and narrower in arid/semiarid and hot and cold areas. We use optimization theory to explain these patterns. We have created a constrained optimization leaf model linking leaf shape to vein structure that is integrated into coupled transpiration and carbon assimilation processes. The model maximizes net leaf carbon gain (NPPleaf) over the loss of xylem water potential. Modeled relations between leaf traits are consistent with empirically observed patterns. As the results of the leaf shape-venation relation, our model further predicts that a broadleaf has overall higher NPPleaf compared to a narrowleaf. In addition, a broadleaf has a lower stomatal resistance compared to a narrowleaf under the same level of constraint. With the same leaf area, a broadleaf will have, on average, larger conduits and lower total leaf xylem resistance and thus be more efficient in water transportation but less resistant to cavitation. By linking venation structure to leaf shape and using water potential as the constraint, our model provides a physical explanation for the general pattern of the covariance of leaf traits through the safety-efficiency trade-off of leaf hydraulic design.
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Affiliation(s)
- Junyan Ding
- Biogeoscience InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Department of Biological SciencesUniversity of CalgaryCalgaryAlbertaCanada
- Lawrence Berkeley National LaboratoryBerkeleyCAUSA
| | - Edward A. Johnson
- Biogeoscience InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Department of Biological SciencesUniversity of CalgaryCalgaryAlbertaCanada
| | - Yvonne E. Martin
- Biogeoscience InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Department of GeographyUniversity of CalgaryCalgaryAlbertaCanada
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41
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Hayat F, Ahmed MA, Zarebanadkouki M, Javaux M, Cai G, Carminati A. Transpiration Reduction in Maize ( Zea mays L) in Response to Soil Drying. FRONTIERS IN PLANT SCIENCE 2020; 10:1695. [PMID: 32038676 PMCID: PMC6989490 DOI: 10.3389/fpls.2019.01695] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 12/02/2019] [Indexed: 05/24/2023]
Abstract
The relationship between leaf water potential, soil water potential, and transpiration depends on soil and plant hydraulics and stomata regulation. Recent concepts of stomatal response to soil drying relate stomatal regulation to plant hydraulics, neglecting the loss of soil hydraulic conductance around the roots. Our objective was to measure the effect of soil drying on the soil-plant hydraulic conductance of maize and to test whether stomatal regulation avoids a loss of soil-plant hydraulic conductance in drying soils. We combined a root pressure chamber, in which the soil-root system is pressurized to maintain the leaf xylem at atmospheric pressure, with sap flow sensors to measure transpiration rate. The method provides accurate and high temporal resolution measurements of the relationship between transpiration rate and xylem leaf water potential. A simple soil-plant hydraulic model describing the flow of water across the soil, root, and xylem was used to simulate the relationship between leaf water potential and transpiration rate. The experiments were carried out with 5-week-old maize grown in cylinders of 9 cm diameter and 30 cm height filled with silty soil. The measurements were performed at four different soil water contents (WC). The results showed that the relationship between transpiration and leaf water potential was linear in wet soils, but as the soil dried, the xylem tension increased, and nonlinearities were observed at high transpiration rates. Nonlinearity in the relationship between transpiration and leaf water potential indicated a decrease in the soil-plant hydraulic conductance, which was explained by the loss of hydraulic conductivity around the roots. The hydraulic model well reproduced the observed leaf water potential. Parallel experiments performed with plants not being pressurized showed that plants closed stomata when the soil-plant hydraulic conductance decreased, maintaining the linearity between leaf water potential and transpiration rate. We conclude that stomata closure during soil drying is caused by the loss of soil hydraulic conductivity in a predictable way.
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Affiliation(s)
- Faisal Hayat
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
| | - Mutez Ali Ahmed
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
- Division of Soil Hydrology, University of Göttingen, Göttingen, Germany
| | | | - Mathieu Javaux
- Earth and Life Institute-Environmental Sciences, Universite Catholique de Louvain, Louvain la Neuve, Belgium
- Agrosphere (IBG-3), Forschungszentrum Juelich GmbH, Juelich, Germany
| | - Gaochao Cai
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
- Division of Soil Hydrology, University of Göttingen, Göttingen, Germany
| | - Andrea Carminati
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
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42
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Papastefanou P, Zang CS, Pugh TAM, Liu D, Grams TEE, Hickler T, Rammig A. A Dynamic Model for Strategies and Dynamics of Plant Water-Potential Regulation Under Drought Conditions. FRONTIERS IN PLANT SCIENCE 2020; 11:373. [PMID: 32411150 PMCID: PMC7199548 DOI: 10.3389/fpls.2020.00373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/16/2020] [Indexed: 05/15/2023]
Abstract
Vegetation responds to drought through a complex interplay of plant hydraulic mechanisms, posing challenges for model development and parameterization. We present a mathematical model that describes the dynamics of leaf water-potential over time while considering different strategies by which plant species regulate their water-potentials. The model has two parameters: the parameter λ describing the adjustment of the leaf water potential to changes in soil water potential, and the parameter Δψww describing the typical 'well-watered' leaf water potentials at non-stressed (near-zero) levels of soil water potential. Our model was tested and calibrated on 110 time-series datasets containing the leaf- and soil water potentials of 66 species under drought and non-drought conditions. Our model successfully reproduces the measured leaf water potentials over time based on three different regulation strategies under drought. We found that three parameter sets derived from the measurement data reproduced the dynamics of 53% of an drought dataset, and 52% of a control dataset [root mean square error (RMSE) < 0.5 MPa)]. We conclude that, instead of quantifying water-potential-regulation of different plant species by complex modeling approaches, a small set of parameters may be sufficient to describe the water potential regulation behavior for large-scale modeling. Thus, our approach paves the way for a parsimonious representation of the full spectrum of plant hydraulic responses to drought in dynamic vegetation models.
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Affiliation(s)
- Phillip Papastefanou
- TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
- *Correspondence: Phillip Papastefanou, ;
| | - Christian S. Zang
- TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Thomas A. M. Pugh
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Institute of Forest Research, University of Birmingham, Birmingham, United Kingdom
| | - Daijun Liu
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Institute of Forest Research, University of Birmingham, Birmingham, United Kingdom
| | - Thorsten E. E. Grams
- TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Thomas Hickler
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt, Germany
- Department of Physical Geography, Goethe University, Frankfurt, Germany
| | - Anja Rammig
- TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
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43
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Rodriguez-Dominguez CM, Brodribb TJ. Declining root water transport drives stomatal closure in olive under moderate water stress. THE NEW PHYTOLOGIST 2020; 225:126-134. [PMID: 31498457 DOI: 10.1111/nph.16177] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 09/01/2019] [Indexed: 05/24/2023]
Abstract
Efficient water transport from soil to leaves sustains stomatal opening and steady-state photosynthesis. The aboveground portion of this pathway is well-described, yet the roots and their connection with the soil are still poorly understood due to technical limitations. Here we used a novel rehydration technique to investigate changes in the hydraulic pathway between roots and soil and within the plant body as individual olive plants were subjected to a range of water stresses. Whole root hydraulic resistance (including the radial pathway from xylem to the soil-root interface) constituted 81% of the whole-plant resistance in unstressed plants, increasing to > 95% under a moderate level of water stress. The decline in this whole root hydraulic conductance occurred in parallel with stomatal closure and contributed significantly to the reduction in canopy conductance according to a hydraulic model. Our results demonstrate that losses in root hydraulic conductance, mainly due to a disconnection from the soil during moderate water stress in olive plants, are profound and sufficient to induce stomatal closure before cavitation occurs. Future studies will determine whether this core regulatory role of root hydraulics exists more generally among diverse plant species.
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Affiliation(s)
- Celia M Rodriguez-Dominguez
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Avenida Reina Mercedes, 10, 41012, Sevilla, Spain
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
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44
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Mackay DS, Savoy PR, Grossiord C, Tai X, Pleban JR, Wang DR, McDowell NG, Adams HD, Sperry JS. Conifers depend on established roots during drought: results from a coupled model of carbon allocation and hydraulics. THE NEW PHYTOLOGIST 2020; 225:679-692. [PMID: 31276231 DOI: 10.1111/nph.16043] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 07/01/2019] [Indexed: 06/09/2023]
Abstract
Trees may survive prolonged droughts by shifting water uptake to reliable water sources, but it is unknown if the dominant mechanism involves activating existing roots or growing new roots during drought, or some combination of the two. To gain mechanistic insights on this unknown, a dynamic root-hydraulic modeling framework was developed that set up a feedback between hydraulic controls over carbon allocation and the role of root growth on soil-plant hydraulics. The new model was tested using a 5 yr drought/heat field experiment on an established piñon-juniper stand with root access to bedrock groundwater. Owing to the high carbon cost per unit root area, modeled trees initialized without adequate bedrock groundwater access experienced potentially lethal declines in water potential, while all of the experimental trees maintained nonlethal water potentials. Simulated trees were unable to grow roots rapidly enough to mediate the hydraulic stress, particularly during warm droughts. Alternatively, modeled trees initiated with root access to bedrock groundwater matched the hydraulics of the experimental trees by increasing their water uptake from bedrock groundwater when soil layers dried out. Therefore, the modeling framework identified a critical mechanism for drought response that required trees to shift water uptake among existing roots rather than growing new roots.
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Affiliation(s)
- D Scott Mackay
- Department of Geography, University at Buffalo, Buffalo, NY, 14261, USA
| | - Philip R Savoy
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Charlotte Grossiord
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Xiaonan Tai
- Department of Geography, University at Buffalo, Buffalo, NY, 14261, USA
| | - Jonathan R Pleban
- Department of Geography, University at Buffalo, Buffalo, NY, 14261, USA
| | - Diane R Wang
- Department of Geography, University at Buffalo, Buffalo, NY, 14261, USA
| | | | - Henry D Adams
- Department of Plant Biology, Ecology, and Evolution, Oklahoma State University, Stillwater, OK, 74078, USA
| | - John S Sperry
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
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45
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Trugman AT, Anderegg LDL, Sperry JS, Wang Y, Venturas M, Anderegg WRL. Leveraging plant hydraulics to yield predictive and dynamic plant leaf allocation in vegetation models with climate change. GLOBAL CHANGE BIOLOGY 2019; 25:4008-4021. [PMID: 31465580 DOI: 10.1111/gcb.14814] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Plant functional traits provide a link in process-based vegetation models between plant-level physiology and ecosystem-level responses. Recent advances in physiological understanding and computational efficiency have allowed for the incorporation of plant hydraulic processes in large-scale vegetation models. However, a more mechanistic representation of water limitation that determines ecosystem responses to plant water stress necessitates a re-evaluation of trait-based constraints for plant carbon allocation, particularly allocation to leaf area. In this review, we examine model representations of plant allocation to leaves, which is often empirically set by plant functional type-specific allometric relationships. We analyze the evolution of the representation of leaf allocation in models of different scales and complexities. We show the impacts of leaf allocation strategy on plant carbon uptake in the context of recent advancements in modeling hydraulic processes. Finally, we posit that deriving allometry from first principles using mechanistic hydraulic processes is possible and should become standard practice, rather than using prescribed allometries. The representation of allocation as an emergent property of scarce resource constraints is likely to be critical to representing how global change processes impact future ecosystem dynamics and carbon fluxes and may reduce the number of poorly constrained parameters in vegetation models.
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Affiliation(s)
- Anna T Trugman
- Department of Geography, University of California Santa Barbara, Santa Barbara, CA, USA
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Leander D L Anderegg
- Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, USA
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
| | - John S Sperry
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Yujie Wang
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Martin Venturas
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
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46
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Perri S, Katul GG, Molini A. Xylem-phloem hydraulic coupling explains multiple osmoregulatory responses to salt stress. THE NEW PHYTOLOGIST 2019; 224:644-662. [PMID: 31349369 DOI: 10.1111/nph.16072] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/11/2019] [Indexed: 06/10/2023]
Abstract
Salinity is known to affect plant productivity by limiting leaf-level carbon exchange, root water uptake, and carbohydrates transport in the phloem. However, the mechanisms through which plants respond to salt exposure by adjusting leaf gas exchange and xylem-phloem flow are still mostly unexplored. A physically based model coupling xylem, leaf, and phloem flows is here developed to explain different osmoregulation patterns across species. Hydraulic coupling is controlled by leaf water potential, ψl , and determined under four different maximization hypotheses: water uptake (1), carbon assimilation (2), sucrose transport (3), or (4) profit function - i.e. carbon gain minus hydraulic risk. All four hypotheses assume that finite transpiration occurs, providing a further constraint on ψl . With increasing salinity, the model captures different transpiration patterns observed in halophytes (nonmonotonic) and glycophytes (monotonically decreasing) by reproducing the species-specific strength of xylem-leaf-phloem coupling. Salt tolerance thus emerges as plant's capability of differentiating between salt- and drought-induced hydraulic risk, and to regulate internal flows and osmolytes accordingly. Results are shown to be consistent across optimization schemes (1-3) for both halophytes and glycophytes. In halophytes, however, profit-maximization (4) predicts systematically higher ψl than (1-3), pointing to the need of an updated definition of hydraulic cost for halophytes under saline conditions.
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Affiliation(s)
- Saverio Perri
- Masdar Institute, Khalifa University of Science and Technology, PO Box 54224, Abu Dhabi, United Arab Emirates
- Department of Civil Infrastructure and Environmental Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates
| | - Gabriel G Katul
- Nicholas School of the Environment, Duke University, Durham, NC, 27710, USA
- Department of Civil and Environmental Engineering, Duke University, Durham, NC, 27708, USA
| | - Annalisa Molini
- Masdar Institute, Khalifa University of Science and Technology, PO Box 54224, Abu Dhabi, United Arab Emirates
- Department of Civil Infrastructure and Environmental Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates
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47
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McDowell NG, Brodribb TJ, Nardini A. Hydraulics in the 21 st century. THE NEW PHYTOLOGIST 2019; 224:537-542. [PMID: 31545889 DOI: 10.1111/nph.16151] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
| | - Timothy J Brodribb
- School of Biological Science, University of Tasmania, Hobart, TAS, Australia
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy
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48
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Wang Y, Sperry JS, Venturas MD, Trugman AT, Love DM, Anderegg WRL. The stomatal response to rising CO2 concentration and drought is predicted by a hydraulic trait-based optimization model. TREE PHYSIOLOGY 2019; 39:1416-1427. [PMID: 30949697 DOI: 10.1093/treephys/tpz038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/29/2019] [Accepted: 03/22/2019] [Indexed: 06/09/2023]
Abstract
Modeling stomatal control is critical for predicting forest responses to the changing environment and hence the global water and carbon cycles. A trait-based stomatal control model that optimizes carbon gain while avoiding hydraulic risk has been shown to perform well in response to drought. However, the model's performance against changes in atmospheric CO2, which is rising rapidly due to human emissions, has yet to be evaluated. The present study tested the gain-risk model's ability to predict the stomatal response to CO2 concentration with potted water birch (Betula occidentalis Hook.) saplings in a growth chamber. The model's performance in predicting stomatal response to changes in atmospheric relative humidity and soil moisture was also assessed. The gain-risk model predicted the photosynthetic assimilation, transpiration rate and leaf xylem pressure under different CO2 concentrations, having a mean absolute percentage error (MAPE) of 25%. The model also predicted the responses to relative humidity and soil drought with a MAPE of 21.9% and 41.9%, respectively. Overall, the gain-risk model had an MAPE of 26.8% compared with the 37.5% MAPE obtained by a standard empirical model of stomatal conductance. Importantly, unlike empirical models, the optimization model relies on measurable physiological traits as inputs and performs well in predicting responses to novel environmental conditions without empirical corrections. Incorporating the optimization model in larger scale models has the potential for improving the simulation of water and carbon cycles.
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Affiliation(s)
- Yujie Wang
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - John S Sperry
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Martin D Venturas
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Anna T Trugman
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - David M Love
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, E Green Street, Athens, GA, USA
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49
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Martinez-Vilalta J, Anderegg WRL, Sapes G, Sala A. Greater focus on water pools may improve our ability to understand and anticipate drought-induced mortality in plants. THE NEW PHYTOLOGIST 2019; 223:22-32. [PMID: 30560995 DOI: 10.1111/nph.15644] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/06/2018] [Indexed: 05/23/2023]
Abstract
Drought-induced tree mortality has major impacts on ecosystem carbon and water cycles, and is expected to increase in forests across the globe with climate change. A large body of research in the past decade has advanced our understanding of plant water and carbon relations under drought. However, despite intense research, we still lack generalizable, cross-scale indicators of mortality risk. In this Viewpoint, we propose that a more explicit consideration of water pools could improve our ability to monitor and anticipate mortality risk. Specifically, we focus on the relative water content (RWC), a classic metric in plant water relations, as a potential indicator of mortality risk that is physiologically relevant and integrates different aspects related to hydraulics, stomatal responses and carbon economy under drought. Measures of plant water content are likely to have a strong mechanistic link with mortality and to be integrative, threshold-prone and relatively easy to measure and monitor at large spatial scales, and may complement current mortality metrics based on water potential, loss of hydraulic conductivity and nonstructural carbohydrates. We discuss some of the potential advantages and limitations of these metrics to improve our capacity to monitor and predict drought-induced tree mortality.
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Affiliation(s)
- Jordi Martinez-Vilalta
- CREAF, Cerdanyola del Valles, 08193, Barcelona, Spain
- Universitat Autònoma de Barcelona, Cerdanyola del Valles, 08193, Barcelona, Spain
| | | | - Gerard Sapes
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
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50
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Kannenberg SA, Novick KA, Phillips RP. Anisohydric behavior linked to persistent hydraulic damage and delayed drought recovery across seven North American tree species. THE NEW PHYTOLOGIST 2019; 222:1862-1872. [PMID: 30664253 DOI: 10.1111/nph.15699] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/15/2019] [Indexed: 05/08/2023]
Abstract
The isohydry-anisohydry spectrum has become a popular way to characterize plant drought responses and recovery processes. Despite the proven utility of this framework for understanding the interconnected physiological changes plants undergo in response to water stress, new challenges have arisen pertaining to the traits and tradeoffs that underlie this concept. To test the utility of this framework for understanding hydraulic traits, drought physiology and recovery, we applied a 6 wk experimental soil moisture reduction to seven tree species followed by a 6 wk recovery period. Throughout, we measured hydraulic traits and monitored changes in gas exchange, leaf water potential, and hydraulic conductivity. Species' hydraulic traits were not coordinated, as some anisohydric species had surprisingly low resistance to embolism (P50 ) and negative safety margins. In addition to widespread hydraulic damage, these species also experienced reductions in photosynthesis and stem water potential during water stress, and delayed recovery time. Given that we observed no benefit of being anisohydric either during or after drought, our results indicate the need to reconsider the traits and tradeoffs that underlie anisohydric behavior, and to consider the environmental, biological and edaphic processes that could allow this strategy to flourish in forests.
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Affiliation(s)
- Steven A Kannenberg
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Kimberly A Novick
- School of Public and Environmental Affairs, Indiana University, Bloomington, IN, 47405, USA
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