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Waite PA, Kumar M, Link RM, Schuldt B. Coordinated hydraulic traits influence the two phases of time to hydraulic failure in five temperate tree species differing in stomatal stringency. Tree Physiol 2024; 44:tpae038. [PMID: 38606678 DOI: 10.1093/treephys/tpae038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 03/08/2024] [Accepted: 03/28/2024] [Indexed: 04/13/2024]
Abstract
Worldwide, forests are increasingly exposed to extreme droughts causing tree mortality. Because of the complex nature of the mechanisms involved, various traits have been linked to tree drought responses with contrasting results. This may be due to species-specific strategies in regulating water potential, a process that unfolds in two distinct phases: a first phase until stomatal closure, and a second phase until reaching lethal xylem hydraulic thresholds. We conducted dry-down experiments with five broadleaved temperate tree species differing in their degree of isohydry to estimate the time to stomatal closure (tsc) and subsequent time to critical hydraulic failure (tcrit). We measured various traits linked to tree drought responses, such as the water potentials at turgor loss point (Ptlp), stomatal closure (Pgs90), and 12%, 50% and 88% loss of xylem hydraulic conductance (P12, P50, P88), hydraulic capacitance (C), minimum leaf conductance (gmin), hydroscape area (HSA) and hydraulic safety margins (HSM). We found that Pgs90 followed previously recorded patterns of isohydry and was associated with HSA. Species ranked from more to less isohydric in the sequence Acer pseudoplatanus < Betula pendula < Tilia cordata < Sorbus aucuparia < Fagus sylvatica. Their degree of isohydry was associated with leaf safety (Ptlp and gmin), drought avoidance (C) and tsc, but decoupled from xylem safety (HSM and P88) and tcrit. Regardless of their stomatal stringency, species with wider HSM and lower P88 reached critical hydraulic failure later. We conclude that the duration of the first phase is determined by stomatal regulation, while the duration of the second phase is associated with xylem safety. Isohydry is thus linked to water use rather than to drought survival strategies, confirming the proposed use of HSA as a complement to HSM for describing plant drought responses before and after stomatal closure.
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Affiliation(s)
- Pierre-André Waite
- Julius-von-Sachs-Institute of Biological Sciences, Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Platz 3, 97082 Würzburg, Germany
- Forest Botany, TUD Dresden University of Technology, Pienner Straße 7, 01737, Tharandt, Germany
- CIRAD, UPR AIDA, 34398 Montpellier, France
| | - Manish Kumar
- Julius-von-Sachs-Institute of Biological Sciences, Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Platz 3, 97082 Würzburg, Germany
- ICAR - Central Soil Salinity Research Institute (CSSRI), Karnal, 132001, India
| | - Roman M Link
- Julius-von-Sachs-Institute of Biological Sciences, Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Platz 3, 97082 Würzburg, Germany
- Forest Botany, TUD Dresden University of Technology, Pienner Straße 7, 01737, Tharandt, Germany
| | - Bernhard Schuldt
- Julius-von-Sachs-Institute of Biological Sciences, Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Platz 3, 97082 Würzburg, Germany
- Forest Botany, TUD Dresden University of Technology, Pienner Straße 7, 01737, Tharandt, Germany
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Ulrich DEM, Grossiord C. Faster drought recovery in anisohydric beech compared with isohydric spruce. Tree Physiol 2023; 43:517-521. [PMID: 36708034 DOI: 10.1093/treephys/tpad009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/06/2023] [Accepted: 01/22/2023] [Indexed: 05/03/2023]
Affiliation(s)
| | - Charlotte Grossiord
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
- École Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering ENAC, 1015 Lausanne, Switzerland
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Salvi AM, Gosetti SG, Smith DD, Adams MA, Givnish TJ, McCulloh KA. Hydroscapes, hydroscape plasticity and relationships to functional traits and mesophyll photosynthetic sensitivity to leaf water potential in Eucalyptus species. Plant Cell Environ 2022; 45:2573-2588. [PMID: 35706133 DOI: 10.1111/pce.14380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 06/06/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Abstract
The isohydric-anisohydric continuum describes the relative stringency of stomatal control of leaf water potential (ψleaf ) during drought. Hydroscape area (HA)-the water potential landscape over which stomata regulate ψleaf -has emerged as a useful metric of the iso/anisohydric continuum because it is strongly linked to several hydraulic, photosynthetic and structural traits. Previous research on HA focused on broad ecological patterns involving several plant clades. Here we investigate the relationships between HA and climatic conditions and functional traits across ecologically diverse but closely related species while accounting for phylogeny. Across a macroclimatic moisture gradient, defined by the ratio of mean annual precipitation to mean annual pan evaporation (P/Ep ), HA decreased with increased P/Ep across 10 Eucalyptus species. Greater anisohydry reflects lower turgor loss points and greater hydraulic safety, mirroring global patterns. Larger HA coincides with mesophyll photosynthetic capacity that is more sensitive to ψleaf . Hydroscapes exhibit little plasticity in response to variation in water supply, and the extent of plasticity does not vary with P/Ep of native habitats. These findings strengthen the case that HA is a useful metric for characterizing drought tolerance and water-status regulation.
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Affiliation(s)
- Amanda M Salvi
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Sophia G Gosetti
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Duncan D Smith
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, USA
- School of Ecosystem and Forest Sciences, University of Melbourne, Creswick, Victoria, Australia
- Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Mark A Adams
- Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Thomas J Givnish
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Chu HH, Farrell C. Fast plants have water-use and drought strategies that balance rainfall retention and drought survival on green roofs. Ecol Appl 2022; 32:e02486. [PMID: 34674341 DOI: 10.1002/eap.2486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 05/05/2021] [Accepted: 05/26/2021] [Indexed: 06/13/2023]
Abstract
Green roofs can improve ecosystem services in cities; however, this depends on appropriate plant selection. For stormwater management, plants should have high water use to maximize retention and also survive dry periods. Plants adapted to wetter habitats develop "fast" traits for growth, whereas plants from drier habitats develop "slow" traits to conserve water use and survive drought. Therefore, we hypothesized that (1) plants with fast traits would have greater water use, (2) plants with slow traits would have greater drought tolerance, (3) fast-slow traits would be consistent across the plant, and (4) fast plants with greater water use could avoid drought stress. We evaluated 14 green roof species in a glasshouse experiment under well-watered (WW) and water-deficit (WD) conditions to determine relationships between fast-slow traits, water use, and drought resistance. Traits measured were shoot dry mass, specific leaf area (SLA), root mass fraction (RMF), and specific root length (SRL). Daily evapotranspiration per shoot dry mass was used to describe water use. Drought resistance was represented by (1) days to stomatal closure; (2) cumulative ET before stomatal closure; and (3) degree of iso-anisohydry (difference between midday leaf water potential (ΨMD ) of WW and WD plants; ΔΨMD ). Plants with greater water use had fast aboveground traits (greater shoot biomass and SLA). Plants with slow traits had greater drought tolerance as plants with lower shoot dry mass closed their stomata later under WD, and plants with greater root allocation were more anisohydric. Fast-slow traits were not consistent across the plant. Although SLA and SRL were positively related, SRL was not related to water use or drought resistance. Shoot dry mass was inversely related to SLA and had a stronger influence on stomatal closure. Though plants with greater water use under well-watered conditions closed their stomates earlier to avoid drought stress, they were not more isohydric (smaller ∆ΨMD ) and did not necessarily use more water under WD. Fast aboveground traits can be used to select green roof plants with high water use that avoid drought stress to optimize rainfall retention without jeopardizing drought survival. This will facilitate rapid plant selection using trait information from online databases.
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Affiliation(s)
- Hsiao-Hsuan Chu
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria, 3121, Australia
| | - Claire Farrell
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria, 3121, Australia
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Collins AD, Ryan MG, Adams HD, Dickman LT, Garcia-Forner N, Grossiord C, Powers HH, Sevanto S, McDowell NG. Foliar respiration is related to photosynthetic, growth and carbohydrate response to experimental drought and elevated temperature. Plant Cell Environ 2021; 44:3623-3635. [PMID: 34506038 DOI: 10.1111/pce.14183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/12/2021] [Accepted: 08/03/2021] [Indexed: 06/13/2023]
Abstract
Short-term plant respiration (R) increases exponentially with rising temperature, but drought could reduce respiration by reducing growth and metabolism. Acclimation may alter these responses. We examined if species with different drought responses would differ in foliar R response to +4.8°C temperature and -45% precipitation in a field experiment with mature piñon and juniper trees, and if any differences between species were related to differences in photosynthesis rates, shoot growth and nonstructural carbohydrates (NSCs). Short-term foliar R had a Q10 of 1.6 for piñon and 2.6 for juniper. Piñon foliar R did not respond to the +4.8°C temperatures, but R increased 1.4× for juniper. Across treatments, piñon foliage had higher growth, lower NSC content, 29% lower photosynthesis rates, and 44% lower R than juniper. Removing 45% precipitation had little impact on R for either species. Species differences in the response of R under elevated temperature were related to substrate availability and stomatal response to leaf water potential. Despite not acclimating to the higher temperature and having higher R than piñon, greater substrate availability in juniper suggests it could supply respiratory demand for much longer than piñon. Species responses will be critical in ecosystem response to a warmer climate.
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Affiliation(s)
- Adam D Collins
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Michael G Ryan
- Department of Ecosystem Science and Sustainability, Colorado State University, Fort Collins, Colorado, USA
- USDA Forest Service, Rocky Mountain Experiment Station, Fort Collins, Colorado, USA
| | - Henry D Adams
- School of the Environment, Washington State University, Pullman, Washington, USA
| | - Lee Turin Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Núria Garcia-Forner
- Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Charlotte Grossiord
- Swiss Federal Research Institute (WSL), Birmensdorf, Switzerland
- Plant Ecology Research Laboratory (PERL), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Heath H Powers
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Nate G McDowell
- Division of Atmospheric Sciences & Global Change, Pacific Northwest National Laboratory, Richland, Washington, USA
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Wu G, Guan K, Li Y, Novick KA, Feng X, McDowell NG, Konings AG, Thompson SE, Kimball JS, De Kauwe MG, Ainsworth EA, Jiang C. Interannual variability of ecosystem iso/ anisohydry is regulated by environmental dryness. New Phytol 2021; 229:2562-2575. [PMID: 33118166 DOI: 10.1111/nph.17040] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/16/2020] [Indexed: 06/11/2023]
Abstract
●Plants are characterized by the iso/anisohydry continuum depending on how they regulate leaf water potential (ΨL ). However, how iso/anisohydry changes over time in response to year-to-year variations in environmental dryness and how such responses vary across different regions remains poorly characterized. ●We investigated how dryness, represented by aridity index, affects the interannual variability of ecosystem iso/anisohydry at the regional scale, estimated using satellite microwave vegetation optical depth (VOD) observations. This ecosystem-level analysis was further complemented with published field observations of species-level ΨL . ●We found different behaviors in the directionality and sensitivity of isohydricity (σ) with respect to the interannual variation of dryness in different ecosystems. These behaviors can largely be differentiated by the average dryness of the ecosystem itself: in mesic ecosystems, σ decreases in drier years with a higher sensitivity to dryness; in xeric ecosystems, σ increases in drier years with a lower sensitivity to dryness. These results were supported by the species-level synthesis. ●Our study suggests that how plants adjust their water use across years - as revealed by their interannual variability in isohydricity - depends on the dryness of plants' living environment. This finding advances our understanding of plant responses to drought at regional scales.
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Affiliation(s)
- Genghong Wu
- College of Agricultural, Consumer and Environmental Sciences, University of Illinois at Urbana Champaign, Urbana, IL, 61801, USA
| | - Kaiyu Guan
- College of Agricultural, Consumer and Environmental Sciences, University of Illinois at Urbana Champaign, Urbana, IL, 61801, USA
- National Center for Supercomputing Applications, University of Illinois at Urbana Champaign, Champaign, IL, 61820, USA
| | - Yan Li
- State Key Laboratory of Earth Surface Processes and Resources Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, 100875, China
| | - Kimberly A Novick
- O'Neill School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - Xue Feng
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Nate G McDowell
- Earth Systems Science Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Alexandra G Konings
- Department of Earth System Science, Stanford University, Stanford, CA, 94305, USA
| | - Sally E Thompson
- Department of Civil and Environmental Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Department of Civil, Environmental and Mining Engineering, University of Western Australia, Crawley, WA, 6009, Australia
| | - John S Kimball
- Numerical Terra dynamic Simulation Group, College of Forestry & Conservation, University of Montana, Missoula, MT, 59812, USA
| | - Martin G De Kauwe
- ARC Australia Centre of Excellence for Climate Extremes, Sydney, NSW, 2052, Australia
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, 2052, Australia
- Evolution and Ecology Research Centre, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Elizabeth A Ainsworth
- Department of Plant Biology, University of Illinois at Urbana Champaign, Urbana, IL, 61801, USA
- USDA ARS Global Change and Photosynthesis Research Unit, Urbana, IL, 61801, USA
| | - Chongya Jiang
- College of Agricultural, Consumer and Environmental Sciences, University of Illinois at Urbana Champaign, Urbana, IL, 61801, USA
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Torres-García MT, Salinas-Bonillo MJ, Gázquez-Sánchez F, Fernández-Cortés Á, Querejeta JI, Cabello J. Squandering water in drylands: the water-use strategy of the phreatophyte Ziziphus lotus in a groundwater-dependent ecosystem. Am J Bot 2021; 108:236-248. [PMID: 33586136 DOI: 10.1002/ajb2.1606] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 10/19/2020] [Indexed: 06/12/2023]
Abstract
PREMISE Water is the most limiting factor in dryland ecosystems, and plants are adapted to cope with this constraint. Particularly vulnerable are phreatophytic plants from groundwater-dependent ecosystems (GDEs) in regions that have to face water regime alterations due to the impacts of climate and land-use changes. METHODS We investigated two aspects related to the water-use strategy of a keystone species that dominates one of the few terrestrial GDEs in European drylands (Ziziphus lotus): where it obtains water and how it regulates its use. We (1) evaluated plants' water sources and use patterns using a multiple-isotope approach (δ2 H, δ18 O, and Δ13 C); (2) assessed the regulation of plant water potential by characterizing the species on an isohydric-anisohydric continuum; and (3) evaluated plants' response to increasing water stress along a depth-to-groundwater (DTGW) gradient by measuring foliar gas exchange and nutrient concentrations. RESULTS Ziziphus lotus behaves as a facultative or partial phreatophyte with extreme anisohydric stomatal regulation. However, as DTGW increased, Z. lotus (1) reduced the use of groundwater, (2) reduced total water uptake, and (3) limited transpiration water loss while increasing water-use efficiency. We also found a physiological threshold at 14 m depth to groundwater, which could indicate maximum rooting length beyond which optimal plant function could not be sustained. CONCLUSIONS Species such as Z. lotus survive by squandering water in drylands because of a substantial groundwater uptake. However, the identification of DTGW thresholds indicates that drawdowns in groundwater level would jeopardize the functioning of the GDE.
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Affiliation(s)
- M Trinidad Torres-García
- Department of Biology and Geology, Universidad de Almería, Carretera de Sacramento s.n, La Cañada de San Urbano, Almería, 04120, Spain
- Andalusian Centre for the Monitoring and Assessment of Global Change (CAESCG), University of Almería, Spain
| | - María J Salinas-Bonillo
- Department of Biology and Geology, Universidad de Almería, Carretera de Sacramento s.n, La Cañada de San Urbano, Almería, 04120, Spain
- Andalusian Centre for the Monitoring and Assessment of Global Change (CAESCG), University of Almería, Spain
| | - Fernando Gázquez-Sánchez
- Department of Biology and Geology, Universidad de Almería, Carretera de Sacramento s.n, La Cañada de San Urbano, Almería, 04120, Spain
- Andalusian Centre for the Monitoring and Assessment of Global Change (CAESCG), University of Almería, Spain
| | - Ángel Fernández-Cortés
- Department of Biology and Geology, Universidad de Almería, Carretera de Sacramento s.n, La Cañada de San Urbano, Almería, 04120, Spain
- Andalusian Centre for the Monitoring and Assessment of Global Change (CAESCG), University of Almería, Spain
| | - José I Querejeta
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), Murcia, Spain
| | - Javier Cabello
- Department of Biology and Geology, Universidad de Almería, Carretera de Sacramento s.n, La Cañada de San Urbano, Almería, 04120, Spain
- Andalusian Centre for the Monitoring and Assessment of Global Change (CAESCG), University of Almería, Spain
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Guo JS, Hultine KR, Koch GW, Kropp H, Ogle K. Temporal shifts in iso/ anisohydry revealed from daily observations of plant water potential in a dominant desert shrub. New Phytol 2020; 225:713-726. [PMID: 31519032 DOI: 10.1111/nph.16196] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/06/2019] [Indexed: 05/25/2023]
Abstract
Plant species are characterized along a spectrum of isohydry to anisohydry depending on their regulation of water potential (Ψ), but the plasticity of hydraulic strategies is largely unknown. The role of environmental drivers was evaluated in the hydraulic behavior of Larrea tridentata, a drought-tolerant desert shrub that withstands a wide range of environmental conditions. With a 1.5 yr time-series of 2324 in situ measurements of daily predawn and midday Ψ, the temporal variability of hydraulic behavior was explored in relation to soil water supply, atmospheric demand and temperature. Hydraulic behavior in Larrea was highly dynamic, ranging from partial isohydry to extreme anisohydry. Larrea exhibited extreme anisohydry under wet soil conditions corresponding to periods of high productivity, whereas partial isohydry was exhibited after prolonged dry or cold conditions, when productivity was low. Environmental conditions can strongly influence plant hydraulic behavior at relatively fast timescales, which enhances our understanding of plant drought responses. Although species may exhibit a dominant hydraulic behavior, variable environmental conditions can prompt plasticity in Ψ regulation, particularly for species in seasonally dry climates.
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Affiliation(s)
- Jessica S Guo
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Kevin R Hultine
- Department of Research, Conservation, and Collections, Desert Botanical Garden, Phoenix, AZ, 85008, USA
| | - George W Koch
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Heather Kropp
- Department of Geography, Colgate University, Hamilton, NY, 13346, USA
| | - Kiona Ogle
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, 86011, USA
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, 86011, USA
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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. New Phytol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Ratzmann G, Meinzer FC, Tietjen B. Iso/ Anisohydry: Still a Useful Concept. Trends Plant Sci 2019; 24:191-194. [PMID: 30797424 DOI: 10.1016/j.tplants.2019.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 12/19/2018] [Accepted: 01/07/2019] [Indexed: 06/09/2023]
Abstract
The iso/anisohydry concept characterizes plants according to their water status regulation. Coexisting definitions and misconceptions have recently led to considerable criticism. We discuss here reasons for the misconceptions, and propose a robust definition of iso/anisohydry using the leaf turgor loss point to integrate the complex interplay of plant hydraulic traits.
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Affiliation(s)
- Gregor Ratzmann
- Freie Universität Berlin, Institute of Biology, 14195 Berlin, Germany; Freie Universität Berlin, Dahlem Centre of Plant Sciences, 14195 Berlin, Germany.
| | - Frederick C Meinzer
- US Department of Agriculture (USDA) Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331, USA
| | - Britta Tietjen
- Freie Universität Berlin, Institute of Biology, 14195 Berlin, Germany; Freie Universität Berlin, Dahlem Centre of Plant Sciences, 14195 Berlin, Germany; Berlin Brandenburg Institute of Advanced Biodiversity Research (BBIB), 14195 Berlin, Germany
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11
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Pivovaroff AL, Cook VMW, Santiago LS. Stomatal behaviour and stem xylem traits are coordinated for woody plant species under exceptional drought conditions. Plant Cell Environ 2018; 41:2617-2626. [PMID: 29904932 DOI: 10.1111/pce.13367] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/04/2018] [Accepted: 06/06/2018] [Indexed: 06/08/2023]
Abstract
Isohydry (maintenance of plant water potential at the cost of carbon gain) and anisohydry (gas exchange maintenance at the cost of declining plant water status) make up two ends of a stomatal drought response strategy continuum. However, few studies have merged measures of stomatal regulation with xylem hydraulic safety strategies based on in situ field measurements. The goal of this study was to characterize the stomatal and xylem hydraulic safety strategies of woody species in the biodiverse Mediterranean-type ecosystem region of California. Measurements were conducted in situ when California was experiencing the most severe drought conditions in the past 1,200 years. We found coordination among stomatal, hydraulic, and standard leaf functional traits. For example, stem xylem vulnerability to cavitation (P50 ) was correlated with the water potential at stomatal closure (Pclose ); more resistant species had a more negative water potential at stomatal closure. The degree of isohydry-anisohydry, defined at Pclose -P50 , was correlated with the hydraulic safety margin across species; more isohydric species had a larger hydraulic safety margin. In addition, we report for the first time Pclose values below -10 MPa. Measuring these traits in a biodiverse region under exceptional drought conditions contributes to our understanding of plant drought responses.
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Affiliation(s)
- Alexandria L Pivovaroff
- Departments of Biology and Environmental Science, Whittier College, Whittier, California
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California
| | - Victoria M W Cook
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California
| | - Louis S Santiago
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California
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Wen J, Chen YM, Tang YK, Wu X, Xie YL, Cui GY. [Characteristics and affecting factors of sap flow density of Pinus tabuliformis and Hippophae rhamnoides in growing season in the hilly region of the Loess Plateau, China]. Ying Yong Sheng Tai Xue Bao 2018; 28:763-771. [PMID: 29741001 DOI: 10.13287/j.1001-9332.201703.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The dynamic changes of sap flow density (Js) of Pinus tabuliformis and Hippophae rhamnoides in plantations from July to September in 2015 was monitored through thermal dissipation probe in the hilly region of the Loess Plateau. In addition, plant physiological characteristics were analyzed to determine the water use types of these two species. The results indicated that the daily changes of Js of P. tabuliformis and H. rhamnoides showed a single peak during both pre- and post-precipitation. The Js of P. tabuliformis in growing season (12.62 mL·m-2·s-1) was significantly higher than that of H. rhamnoides (2.60 mL·m-2·s-1). The Js of these two species were significantly positively correlated with photosynthetic active radiation, vapor pressure deficit, soil volume-tric water content (SWC). The Js of these two species were mainly influenced by meteorological factors during pre- and post-precipitation in both August and September. The contribution of SWC to Js of H. rhamnoides increased by 4.2% after precipitation in September, but the contribution of SWC to Js of P. tabuliformis decreased by 0.3% after precipitation in both August and September, respectively. Meanwhile, P. tabuliformis showed significantly higher water potential in midday leaf, but lower coefficient of variation (7.3%) than H. rhamnoides with the coefficient of variation of 11.7%. However, H. rhamnoides exhibited higher leaf stomatal conductance. Thus, P. tabuliformis and H. rhamnoides could be considered as isohydry and anisohydry species, respectively.
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Affiliation(s)
- Jie Wen
- College of Fores-try, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yun Ming Chen
- Research Center of Institute of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, Yangling 712100, Shaanxi, China.,Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China
| | - Ya Kun Tang
- Research Center of Institute of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, Yangling 712100, Shaanxi, China.,Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China
| | - Xu Wu
- Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China
| | - Yu Li Xie
- Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China
| | - Gao Yang Cui
- Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China
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Meinzer FC, Smith DD, Woodruff DR, Marias DE, McCulloh KA, Howard AR, Magedman AL. Stomatal kinetics and photosynthetic gas exchange along a continuum of isohydric to anisohydric regulation of plant water status. Plant Cell Environ 2017; 40:1618-1628. [PMID: 28426140 DOI: 10.1111/pce.12970] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/04/2017] [Accepted: 04/10/2017] [Indexed: 05/18/2023]
Abstract
Species' differences in the stringency of stomatal control of plant water potential represent a continuum of isohydric to anisohydric behaviours. However, little is known about how quasi-steady-state stomatal regulation of water potential may relate to dynamic behaviour of stomata and photosynthetic gas exchange in species operating at different positions along this continuum. Here, we evaluated kinetics of light-induced stomatal opening, activation of photosynthesis and features of quasi-steady-state photosynthetic gas exchange in 10 woody species selected to represent different degrees of anisohydry. Based on a previously developed proxy for the degree of anisohydry, species' leaf water potentials at turgor loss, we found consistent trends in photosynthetic gas exchange traits across a spectrum of isohydry to anisohydry. More anisohydric species had faster kinetics of stomatal opening and activation of photosynthesis, and these kinetics were closely coordinated within species. Quasi-steady-state stomatal conductance and measures of photosynthetic capacity and performance were also greater in more anisohydric species. Intrinsic water-use efficiency estimated from leaf gas exchange and stable carbon isotope ratios was lowest in the most anisohydric species. In comparisons between gas exchange traits, species rankings were highly consistent, leading to species-independent scaling relationships over the range of isohydry to anisohydry observed.
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Affiliation(s)
- Frederick C Meinzer
- Pacific Northwest Research Station, USDA Forest Service, Corvallis, OR, 97331, USA
| | - Duncan D Smith
- Department of Botany, University of Wisconsin, Madison, WI, 53706, USA
| | - David R Woodruff
- Pacific Northwest Research Station, USDA Forest Service, Corvallis, OR, 97331, USA
| | - Danielle E Marias
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Katherine A McCulloh
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Ava R Howard
- Department of Biology, Western Oregon University, Monmouth, OR, 97361, USA
| | - Alicia L Magedman
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
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Martínez-Vilalta J, Garcia-Forner N. Water potential regulation, stomatal behaviour and hydraulic transport under drought: deconstructing the iso/anisohydric concept. Plant Cell Environ 2017; 40:962-976. [PMID: 27739594 DOI: 10.1111/pce.12846] [Citation(s) in RCA: 179] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 10/03/2016] [Accepted: 10/04/2016] [Indexed: 05/02/2023]
Abstract
In this review, we address the relationship between stomatal behaviour, water potential regulation and hydraulic transport in plants, focusing on the implications for the iso/anisohydric classification of plant drought responses at seasonal timescales. We first revise the history of the isohydric concept and its possible definitions. Then, we use published data to answer two main questions: (1) is greater stomatal control in response to decreasing water availability associated with a tighter regulation of leaf water potential (ΨL ) across species? and (2) is there an association between tighter ΨL regulation (~isohydric behaviour) and lower leaf conductance over time during a drought event? These two questions are addressed at two levels: across species growing in different sites and comparing only species coexisting at a given site. Our analyses show that, across species, a tight regulation of ΨL is not necessarily associated with greater stomatal control or with more constrained assimilation during drought. Therefore, iso/anisohydry defined in terms of ΨL regulation cannot be used as an indicator of a specific mechanism of drought-induced mortality or as a proxy for overall plant vulnerability to drought.
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Affiliation(s)
- Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès, Barcelona, E-08193, Spain
- Universitat Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, E-08193, Spain
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Meinzer FC, Woodruff DR, Marias DE, McCulloh KA, Sevanto S. Dynamics of leaf water relations components in co-occurring iso- and anisohydric conifer species. Plant Cell Environ 2014; 37:2577-86. [PMID: 24661116 DOI: 10.1111/pce.12327] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 03/13/2014] [Accepted: 03/17/2014] [Indexed: 05/20/2023]
Abstract
Because iso- and anisohydric species differ in stomatal regulation of the rate and magnitude of fluctuations in shoot water potential, they may be expected to show differences in the plasticity of their shoot water relations components, but explicit comparisons of this nature have rarely been made. We subjected excised shoots of co-occurring anisohydric Juniperus monosperma and isohydric Pinus edulis to pressure-volume analysis with and without prior artificial rehydration. In J. monosperma, the shoot water potential at turgor loss (Ψ(TLP)) ranged from -3.4 MPa in artificially rehydrated shoots to -6.6 MPa in shoots with an initial Ψ of -5.5 MPa, whereas in P. edulis mean Ψ(TLP) remained at ∼ -3.0 MPa over a range of initial Ψ from -0.1 to -2.3 MPa. The shoot osmotic potential at full turgor and the bulk modulus of elasticity also declined sharply with shoot Ψ in J. monosperma, but not in P. edulis. The contrasting behaviour of J. monosperma and P. edulis reflects differences in their capacity for homeostatic regulation of turgor that may be representative of aniso- and isohydric species in general, and may also be associated with the greater capacity of J. monosperma to withstand severe drought.
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Affiliation(s)
- Frederick C Meinzer
- USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR, 97331, USA
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