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Niu F, Pierce NA, Okin GS, Archer SR, Fischella MR, Nadoum S. Sandblasting promotes shrub encroachment in arid grasslands. THE NEW PHYTOLOGIST 2023; 240:1817-1829. [PMID: 37658674 DOI: 10.1111/nph.19238] [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: 11/30/2022] [Accepted: 08/15/2023] [Indexed: 09/03/2023]
Abstract
Shrub encroachment is a common ecological state transition in global drylands and has myriad adverse effects on grasslands and the services they provide. This physiognomic shift is often ascribed to changes in climate (e.g. precipitation) and disturbance regimes (e.g. grazing and fire), but this remains debated. Aeolian processes are known to impact resource distribution in drylands, but their potential role in grassland-to-shrubland state changes has received little attention. We quantified the effects of 'sandblasting' (abrasive damage by wind-blown soil) on the ecophysiology of dryland grass vs shrub functional types using a portable wind tunnel to test the hypothesis that grasses would be more susceptible to sandblasting than shrubs and, thus, reinforce transitions to shrub dominance in wind-erodible grasslands when climate- or disturbance-induced reductions in ground cover occur. Grasses and shrubs responded differently to sandblasting, wherein water-use efficiency declined substantially in grasses, but only slightly in shrubs, owing to grasses having greater increases in day/nighttime leaf conductance and transpiration. The differential ecophysiological response to sandblasting exhibited by grass and shrub functional types could consequently alter the vegetation dynamics in dryland grasslands in favour of the xerophytic shrubs. Sandblasting could thus be an overlooked driver of shrub encroachment in wind-erodible grasslands.
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Affiliation(s)
- Furong Niu
- College of Forestry, Gansu Agricultural University, Lanzhou, Gansu, 730070, China
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
| | - Nathan A Pierce
- USDA-Agricultural Research Service, Southwest Watershed Research Center, Tucson, AZ, 85719, USA
| | - Gregory S Okin
- Department of Geography, University of California, Los Angeles, CA, 90095, USA
| | - Steven R Archer
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
| | - Michael R Fischella
- Department of Geography, University of California, Los Angeles, CA, 90095, USA
| | - Shereen Nadoum
- Department of Geography, University of California, Los Angeles, CA, 90095, USA
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Yan Y, Ryu Y, Dechant B, Li B, Kim J. Dark respiration explains nocturnal stomatal conductance in rice regardless of drought and nutrient stress. PLANT, CELL & ENVIRONMENT 2023; 46:3748-3759. [PMID: 37651619 DOI: 10.1111/pce.14710] [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: 10/21/2022] [Revised: 06/20/2023] [Accepted: 08/23/2023] [Indexed: 09/02/2023]
Abstract
The ecological mechanism underlying nocturnal stomatal conductance (gsn ) in C3 and C4 plants remains elusive. In this study, we proposed a 'coordinated leaf trait' hypothesis to explain gsn in rice plants. We conducted an open-field experiment by applying drought, nutrient stress and the combined drought-nutrient stress. We found that gsn was neither strongly reduced by drought nor consistently increased by nutrient stress. With the aforementioned multiple abiotic stressors considered as random effects, gsn exhibited a strong positive correlation with dark respiration (Rn ). Notably, gsn primed early morning (5:00-7:00) photosynthesis through faster stomatal response time. This photosynthesis priming effect diminished after mid-morning (9:00). Leaves were cooled by gsn -derived transpiration. However, our results clearly suggest that evaporative cooling did not reduce dark respiration cost. Our results indicate that gsn is more closely related to carbon respiration and assimilation than water and nutrient availability, and that dark respiration can explain considerable variation of gsn .
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Affiliation(s)
- Yulin Yan
- Interdisciplinary Program in Agricultural and Forest Meteorology, Seoul National University, Seoul, South Korea
| | - Youngryel Ryu
- Interdisciplinary Program in Agricultural and Forest Meteorology, Seoul National University, Seoul, South Korea
- Department of Landscape Architecture and Rural Systems Engineering, Seoul National University, Seoul, South Korea
- Interdisciplinary Program in Landscape Architecture, Seoul National University, Seoul, South Korea
| | - Benjamin Dechant
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
- German Centre for Integrative Biodiversity Research, Leipzig, Germany
- Leipzig University, Leipzig, Germany
| | - Bolun Li
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Jongmin Kim
- Interdisciplinary Program in Landscape Architecture, Seoul National University, Seoul, South Korea
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3
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Potkay A, Feng X. Dynamically optimizing stomatal conductance for maximum turgor-driven growth over diel and seasonal cycles. AOB PLANTS 2023; 15:plad044. [PMID: 37899972 PMCID: PMC10601388 DOI: 10.1093/aobpla/plad044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 07/04/2023] [Indexed: 10/31/2023]
Abstract
Stomata have recently been theorized to have evolved strategies that maximize turgor-driven growth over plants' lifetimes, finding support through steady-state solutions in which gas exchange, carbohydrate storage and growth have all reached equilibrium. However, plants do not operate near steady state as plant responses and environmental forcings vary diurnally and seasonally. It remains unclear how gas exchange, carbohydrate storage and growth should be dynamically coordinated for stomata to maximize growth. We simulated the gas exchange, carbohydrate storage and growth that dynamically maximize growth diurnally and annually. Additionally, we test whether the growth-optimization hypothesis explains nocturnal stomatal opening, particularly through diel changes in temperature, carbohydrate storage and demand. Year-long dynamic simulations captured realistic diurnal and seasonal patterns in gas exchange as well as realistic seasonal patterns in carbohydrate storage and growth, improving upon unrealistic carbohydrate responses in steady-state simulations. Diurnal patterns of carbohydrate storage and growth in day-long simulations were hindered by faulty modelling assumptions of cyclic carbohydrate storage over an individual day and synchronization of the expansive and hardening phases of growth, respectively. The growth-optimization hypothesis cannot currently explain nocturnal stomatal opening unless employing corrective 'fitness factors' or reframing the theory in a probabilistic manner, in which stomata adopt an inaccurate statistical 'memory' of night-time temperature. The growth-optimization hypothesis suggests that diurnal and seasonal patterns of stomatal conductance are driven by a dynamic carbon-use strategy that seeks to maintain homeostasis of carbohydrate reserves.
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Affiliation(s)
- Aaron Potkay
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Twin Cities, 500 Pillsbury Drive S.E., Minneapolis, MN 55455, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Twin Cities, 23rd Ave SE, Minneapolis, MN 55414, USA
| | - Xue Feng
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Twin Cities, 500 Pillsbury Drive S.E., Minneapolis, MN 55455, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Twin Cities, 23rd Ave SE, Minneapolis, MN 55414, USA
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Kupper P, Tullus A, Rohula-Okunev G. Night-time water relations and gas exchange in cut shoots of five boreal dwarf shrub species: impact of soil water availability. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2023; 29:1193-1203. [PMID: 37829697 PMCID: PMC10564692 DOI: 10.1007/s12298-023-01350-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 08/03/2023] [Accepted: 08/21/2023] [Indexed: 10/14/2023]
Abstract
Recent findings suggest that drought may affect plants' daytime and night-time stomatal regulation differently. However, knowledge of night-time stomatal behaviour in dwarf shrubs growing in boreal ecosystems is lacking. We sampled cut shoots from dwarf shrub species to elucidate their capacity to transpire at night and the effect of drought on stomatal regulation. The shoots' water relations and gas exchange were measured under controlled conditions in a growth chamber. The studied species demonstrated considerable differences in their diurnal water use. The night-time water use percentage of daytime water use (NWU) reached up to 90% in Andromeda polifolia and Vaccinium uliginosum. In Rhododendron tomentosum, Vaccinium myrtillus and Chamaedaphne calyculata, the NWU was 62, 27 and 26%, respectively. The shoots of C. calyculata showed a significant increase (P < 0.001) in the transpiration rate (E) during the night. However, in R. tomentosum, a decrease (P < 0.05) in nightly E was observed. The shoot conductance (g) at the end of the night was lower than daytime g in all studied species, but the difference was not significant for V. uliginosum. Across the species, NWU was negatively related (P < 0.001) to the soil volumetric water content (SWC) in the plant habitat. However, daytime E and g were positively related (P < 0.05) to the habitat SWC. Only in V. myrtillus was night-time E higher (P < 0.05) in dry conditions than in wet conditions. Our results demonstrate high variability in diurnal water relations in dwarf shrubs, which can keep stomata open in the dark even when drought limits daytime g and E.
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Affiliation(s)
- Priit Kupper
- Institute of Ecology and Earth Sciences, University of Tartu, Liivi 2, 50409 Tartu, Estonia
| | - Arvo Tullus
- Institute of Ecology and Earth Sciences, University of Tartu, Liivi 2, 50409 Tartu, Estonia
| | - Gristin Rohula-Okunev
- Institute of Ecology and Earth Sciences, University of Tartu, Liivi 2, 50409 Tartu, Estonia
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Masutomi Y. The appropriate analytical solution for coupled leaf photosynthesis and stomatal conductance models for C3 plants. Ecol Modell 2023. [DOI: 10.1016/j.ecolmodel.2023.110306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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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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Ávila-Lovera E, Winter K, Goldsmith GR. Evidence for phylogenetic signal and correlated evolution in plant-water relation traits. THE NEW PHYTOLOGIST 2023; 237:392-407. [PMID: 36271615 DOI: 10.1111/nph.18565] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
Evolutionary relationships are likely to play a significant role in shaping plant physiological and structural traits observed in contemporary taxa. We review research on phylogenetic signal and correlated evolution in plant-water relation traits, which play important roles in allowing plants to acquire, use, and conserve water. We found more evidence for a phylogenetic signal in structural traits (e.g. stomatal length and stomatal density) than in physiological traits (e.g. stomatal conductance and water potential at turgor loss). Although water potential at turgor loss is the most-studied plant-water relation trait in an evolutionary context, it is the only trait consistently found to not have a phylogenetic signal. Correlated evolution was common among traits related to water movement efficiency and hydraulic safety in both leaves and stems. We conclude that evidence for phylogenetic signal varies depending on: the methodology used for its determination, that is, model-based approaches to determine phylogenetic signal such as Blomberg's K or Pagel's λ vs statistical approaches such as ANOVAs with taxonomic classification as a factor; on the number of taxa studied (size of the phylogeny); and the setting in which plants grow (field vs common garden). More explicitly and consistently considering the role of evolutionary relationships in shaping plant ecophysiology could improve our understanding of how traits compare among species, how traits are coordinated with one another, and how traits vary with the environment.
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Affiliation(s)
- Eleinis Ávila-Lovera
- Schmid College of Science and Technology, Chapman University, Orange, CA, 92866, USA
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancon, Panama
| | - Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancon, Panama
| | - Gregory R Goldsmith
- Schmid College of Science and Technology, Chapman University, Orange, CA, 92866, USA
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Datta S, Sharma A, Sinha B. Nocturnal pollutant uptake contributes significantly to the total stomatal uptake of Mangifera indica. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 310:119902. [PMID: 35940482 DOI: 10.1016/j.envpol.2022.119902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/26/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
DO3SE (Deposition of Ozone for Stomatal Exchange), is a dry deposition model, designed to assess tropospheric ozone risk to vegetation, and is based on two alternative algorithms to estimate stomatal conductance: multiplicative and photosynthetic. The multiplicative model has been argued to perform better for leaf-level and regional-level application. In this study, we demonstrate that the photosynthetic model is superior to the multiplicative model even for leaf-level studies using measurements performed on Mangifera indica. We find that the multiplicative model overestimates the daytime stomatal conductance, when compared with measured stomatal conductance and prescribes zero conductance at night while measurements show an average conductance of 100 mmol(H2O)m-2s-1 between 9 p.m. and 4 a.m. The daytime overestimation of the multiplicative model can be significantly reduced when the model is modified to include a response function for ozone-induced stomatal closure. However, nighttime pollutant uptake fluxes can only be accurately assessed with the photosynthetic model which includes the stomatal opening at night during respiration and is capable of reproducing the measured nighttime stomatal conductance. At our site, the nocturnal flux contributes 64%, 39%, 46%, and 88% of the total for NO2 uptake in winter, summer, monsoon, and post-monsoon, respectively. For SO2, nocturnal uptake amounts to 35%, 28%, 28%, and 44% in winter, summer, monsoon, and post-monsoon, respectively while for ozone the nighttime uptake contributes 30%, 17%, 18%, and 29% of the total stomatal uptake in winter, summer, monsoon, and post-monsoon respectively.
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Affiliation(s)
- Savita Datta
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S.A.S Nagar, Punjab, 140306, India
| | - Anita Sharma
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S.A.S Nagar, Punjab, 140306, India
| | - Baerbel Sinha
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S.A.S Nagar, Punjab, 140306, India.
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9
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Bright RM, Miralles DG, Poyatos R, Eisner S. Simple Models Outperform More Complex Big-Leaf Models of Daily Transpiration in Forested Biomes. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2022GL100100. [PMID: 36583013 PMCID: PMC9786846 DOI: 10.1029/2022gl100100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/01/2022] [Accepted: 09/06/2022] [Indexed: 06/17/2023]
Abstract
Transpiration makes up the bulk of total evaporation in forested environments yet remains challenging to predict at landscape-to-global scales. We harnessed independent estimates of daily transpiration derived from co-located sap flow and eddy-covariance measurement systems and applied the triple collocation technique to evaluate predictions from big leaf models requiring no calibration. In total, four models in 608 unique configurations were evaluated at 21 forested sites spanning a wide diversity of biophysical attributes and environmental backgrounds. We found that simpler models that neither explicitly represented aerodynamic forcing nor canopy conductance achieved higher accuracy and signal-to-noise levels when optimally configured (rRMSE = 20%; R 2 = 0.89). Irrespective of model type, optimal configurations were those making use of key plant functional type dependent parameters, daily LAI, and constraints based on atmospheric moisture demand over soil moisture supply. Our findings have implications for more informed water resource management based on hydrological modeling and remote sensing.
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Affiliation(s)
- Ryan M. Bright
- Department of Forests and ClimateDivision of Forestry and Forest ResourcesNorwegian Institute of Bioeconomy Research (NIBIO)ÅsNorway
| | - Diego G. Miralles
- Hydro‐Climate Extremes Lab (H‐CEL)Department of the EnvironmentGhent UniversityGhentBelgium
| | - Rafael Poyatos
- CREAFCerdanyola del VallèsSpain
- Universitat Autònoma de BarcelonaCerdanyola del VallèsSpain
| | - Stephanie Eisner
- Department of Forests and ClimateDivision of Forestry and Forest ResourcesNorwegian Institute of Bioeconomy Research (NIBIO)ÅsNorway
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10
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Du Y, Lu R, Sun H, Cui E, Yan L, Xia J. Plant photosynthetic overcompensation under nocturnal warming: lack of evidence in subtropical evergreen trees. ANNALS OF BOTANY 2022; 130:109-119. [PMID: 35690359 PMCID: PMC9295921 DOI: 10.1093/aob/mcac075] [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: 03/30/2022] [Accepted: 06/09/2022] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND AIMS Increased plant photosynthesis under nocturnal warming is a negative feedback mechanism to overcompensate for night-time carbon loss to mitigate climate warming. This photosynthetic overcompensation effect has been observed in dry deciduous ecosystems but whether it exists in subtropical wet forest trees is unclear. METHODS Two subtropical evergreen tree species (Schima superba and Castanopsis sclerophylla) were grown in a greenhouse and exposed to ambient and elevated night-time temperature. The occurrence of the photosynthetic overcompensation effect was determined by measuring daytime and night-time leaf gas exchange and non-structural carbohydrate (NSC) concentration. KEY RESULTS A reduction in leaf photosynthesis for both species and an absence of persistent photosynthetic overcompensation were observed. The photosynthetic overcompensation effect was transient in S. superba due to respiratory acclimation and stomatal limitation. For S. superba, nocturnal warming resulted in insufficient changes in night-time respiration and NSC concentration to stimulate overcompensation and inhibited leaf stomatal conductance by increasing the leaf-to-air vapour pressure deficit. CONCLUSIONS The results indicate that leaf stomatal conductance is important for the photosynthetic overcompensation effect in different tree species. The photosynthetic overcompensation effect under nocturnal warming may be a transient occurrence rather than a persistent mechanism in subtropical forest ecosystems.
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Affiliation(s)
- Ying Du
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Ruiling Lu
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Huanfa Sun
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Erqian Cui
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Liming Yan
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
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11
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Lamour J, Davidson KJ, Ely KS, Le Moguédec G, Leakey ADB, Li Q, Serbin SP, Rogers A. An improved representation of the relationship between photosynthesis and stomatal conductance leads to more stable estimation of conductance parameters and improves the goodness-of-fit across diverse data sets. GLOBAL CHANGE BIOLOGY 2022; 28:3537-3556. [PMID: 35090072 DOI: 10.1111/gcb.16103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 01/17/2022] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Stomata play a central role in surface-atmosphere exchange by controlling the flux of water and CO2 between the leaf and the atmosphere. Representation of stomatal conductance (gsw ) is therefore an essential component of models that seek to simulate water and CO2 exchange in plants and ecosystems. For given environmental conditions at the leaf surface (CO2 concentration and vapor pressure deficit or relative humidity), models typically assume a linear relationship between gsw and photosynthetic CO2 assimilation (A). However, measurement of leaf-level gsw response curves to changes in A are rare, particularly in the tropics, resulting in only limited data to evaluate this key assumption. Here, we measured the response of gsw and A to irradiance in six tropical species at different leaf phenological stages. We showed that the relationship between gsw and A was not linear, challenging the key assumption upon which optimality theory is based-that the marginal cost of water gain is constant. Our data showed that increasing A resulted in a small increase in gsw at low irradiance, but a much larger increase at high irradiance. We reformulated the popular Unified Stomatal Optimization (USO) model to account for this phenomenon and to enable consistent estimation of the key conductance parameters g0 and g1 . Our modification of the USO model improved the goodness-of-fit and reduced bias, enabling robust estimation of conductance parameters at any irradiance. In addition, our modification revealed previously undetectable relationships between the stomatal slope parameter g1 and other leaf traits. We also observed nonlinear behavior between A and gsw in independent data sets that included data collected from attached and detached leaves, and from plants grown at elevated CO2 concentration. We propose that this empirical modification of the USO model can improve the measurement of gsw parameters and the estimation of plant and ecosystem-scale water and CO2 fluxes.
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Affiliation(s)
- Julien Lamour
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Kenneth J Davidson
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, USA
| | - Kim S Ely
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Gilles Le Moguédec
- AMAP, Université Montpellier, INRAE, Cirad CNRS, IRD, Montpellier, France
| | - Andrew D B Leakey
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Qianyu Li
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Shawn P Serbin
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Alistair Rogers
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
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12
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Su Y, Wang X, Sun Y, Wu H. Sap Flow Velocity in Fraxinus pennsylvanica in Response to Water Stress and Microclimatic Variables. FRONTIERS IN PLANT SCIENCE 2022; 13:884526. [PMID: 35620691 PMCID: PMC9127660 DOI: 10.3389/fpls.2022.884526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 04/14/2022] [Indexed: 06/15/2023]
Abstract
In arid and semiarid regions with water shortage, forestry development is limited by water availability. Understanding how tree sap flow responds to water stress and microclimatic variables is essential for the management of trees and the understanding of the eco-physiological properties of trees in arid areas. In the city of Tianjin in northern China, we measured the sap flow of Fraxinus pennsylvanica, a widely distributed urban greening tree species in semiarid regions of China. We measured the sap flow in four F. pennsylvanica trees over 6 months (April-September 2021), using a thermal diffusion probe method, and simultaneously monitored microclimatic variables and soil moisture. Results indicated that high nighttime sap flow velocity might be produced under the water stress condition. In addition, the nighttime sap flow velocity under the water stress condition was more susceptible to the combined effects of meteorological factors at night. The daytime sap flow velocity exerted a highly significant positive effect on the nighttime sap flow velocity during the whole research period, and the model fit was higher in the early growing season than that in the late growing season (early growing season: R 2 = 0.51, P < 0.01; late growing season: R 2 = 0.36, P < 0.01). Vapor pressure deficit had a positive effect on daytime sap flow. However, net vapor pressure deficit restrained daytime sap flow velocity when the intercorrelation between the microclimatic variables was removed. Our study highlights that drought areas perhaps have higher nighttime sap flow and that more emphasis should be placed on nighttime sap flow and the response of nighttime sap flow to microclimatic variables. In addition, the influence of other microclimatic variables on vapor pressure deficit needs to be considered when analyzing the relationship between daytime sap flow and vapor pressure deficit. An increase in net VPD can suppress the daytime sap flow.
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13
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McAusland L, Smith KE, Williams A, Molero G, Murchie EH. Nocturnal stomatal conductance in wheat is growth-stage specific and shows genotypic variation. THE NEW PHYTOLOGIST 2021; 232:162-175. [PMID: 34143507 DOI: 10.1111/nph.17563] [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: 03/03/2021] [Accepted: 06/09/2021] [Indexed: 06/12/2023]
Abstract
Nocturnal stomatal conductance (gsn ) represents a significant source of water loss, with implications for metabolism, thermal regulation and water-use efficiency. With increasing nocturnal temperatures due to climate change, it is vital to identify and understand variation in the magnitude and responses of gsn in major crops. We assessed interspecific variation in gsn and daytime stomatal conductance (gs ) in a wild relative and modern spring wheat genotype. To investigate intraspecific variation, we grew six modern wheat genotypes and two landraces under well watered, simulated field conditions. For the diurnal data, higher gsn in the wild relative was associated with significantly lower nocturnal respiration and higher daytime CO2 assimilation while both species exhibited declines in gsn post-dusk and pre-dawn. Lifetime gsn achieved rates of 5.7-18.9% of gs . Magnitude of gsn was genotype specific 'and positively correlated with gs . gsn and gs were significantly higher on the adaxial surface. No relationship was determined between harvest characteristics, stomatal morphology and gsn , while cuticular conductance was genotype specific. Finally, for the majority of genotypes, gsn declined with age. Here we present the discovery that variation in gsn occurs across developmental, morphological and temporal scales in nonstressed wheat, presenting opportunities for exploiting intrinsic variation under heat or water stressed conditions.
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Affiliation(s)
- Lorna McAusland
- School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK
| | - Kellie E Smith
- School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK
| | - Alexander Williams
- School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK
| | - Gemma Molero
- International Maize and Wheat Improvement Center (CIMMYT), Km. 45, Carretera Mexico, El Batan, Texcoco, CP 56237, Mexico
| | - Erik H Murchie
- School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK
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14
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Zhang Q, Yang Y, Peng S, Li Y. Nighttime transpirational cooling enabled by circadian regulation of stomatal conductance is related to stomatal anatomy and leaf morphology in rice. PLANTA 2021; 254:12. [PMID: 34165635 DOI: 10.1007/s00425-021-03661-w] [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: 03/21/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
Rice genotypes with larger stomata maintain higher nocturnal stomatal conductance, thus having lower nocturnal leaf temperature via transpirational cooling. Incomplete night stomatal closure has been widely observed, but the mechanisms and functions of nocturnal stomatal conductance (gs,n) are not fully understood. Stomatal anatomy, leaf morphology, gs,n and nocturnal leaf temperature (Tleaf,n) were measured in 30 Oryza genotypes. Nocturnal leaf conductance (gn) showed a significant circadian rhythm; it gradually increased by 58% from 20:30 to 04:30. Contrary to cuticular conductance (gcut), gs,n was highly correlated with gn. Moreover, gs,n accounted for 76% of gn. Tleaf,n was significantly lower than the air temperature, and was negatively correlated with both gs,n and nocturnal transpiration rate (En). gs,n was positively correlated with stomatal size, intervein distance between major veins (IVDmajor), leaf thickness (LT), individual leaf area (LA), and leaf width (LW). It was also found negatively correlated with stomatal density. Reversely, Tleaf,n was negatively correlated with stomatal size, IVDmajor, intervein distance between minor veins, LA and LW. Tleaf,n presented a positive correlation with stomatal density. This study highlights the importance of stomatal anatomy and leaf morphology on regulating gs,n and Tleaf,n. The underlying mechanisms to the determinants of gs,n and the physiological and ecological functions of the Tleaf,n regulation on rice growth and production were carefully discussed.
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Affiliation(s)
- Qiangqiang Zhang
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Yuhan Yang
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Shaobing Peng
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Yong Li
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
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15
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Wang Y, Anderegg WRL, Venturas MD, Trugman AT, Yu K, Frankenberg C. Optimization theory explains nighttime stomatal responses. THE NEW PHYTOLOGIST 2021; 230:1550-1561. [PMID: 33576001 DOI: 10.1111/nph.17267] [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: 10/22/2020] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Nocturnal transpiration is widely observed across species and biomes, and may significantly impact global water, carbon, and energy budgets. However, it remains elusive why plants lose water at night and how to model it at large scales. We hypothesized that plants optimize nighttime leaf diffusive conductance (gwn ) to balance potential daytime photosynthetic benefits and nocturnal transpiration benefits. We quantified nighttime benefits from respiratory reductions due to evaporative leaf cooling. We described nighttime costs in terms of a reduced carbon gain during the day because of water use at night. We measured nighttime stomatal responses and tested our model with water birch (Betula occidentalis) saplings grown in a glasshouse. The gwn of water birch decreased with drier soil, higher atmospheric CO2 , wetter air, lower leaf temperature, and lower leaf respiration rate. Our model predicted all these responses correctly, except for the response of gwn to air humidity. Our results also suggested that the slow decrease in gwn after sunset could be associated with decreasing leaf respiration. The optimality-based nocturnal transpiration model smoothly integrates with daytime stomatal optimization approaches, and thus has the potential to quantitatively predict nocturnal transpiration across space and time.
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Affiliation(s)
- Yujie Wang
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, 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
| | - Kailiang Yu
- Le Laboratoire des Sciences du Climat et de l'Environnement, IPSL-LSCECEA/CNRS/UVSQ Saclay, Gif-sur-Yvette, 91191, France
| | - Christian Frankenberg
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
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16
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Kupper P, Kaasik A, Kukumägi M, Rohula-Okunev G, Rusalepp L, Sõber A. Predawn leaf conductance depends on previous day irradiance but is not related to growth in aspen saplings grown under artificially manipulated air humidity. FUNCTIONAL PLANT BIOLOGY : FPB 2021; 48:422-433. [PMID: 33287949 DOI: 10.1071/fp20254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
Recent studies have suggested that predawn stomatal opening may enhance early-morning photosynthesis (A) and improve the relative growth rate of trees. However, the causality between night-time stomatal conductance, A, and tree growth is disputable because stomatal opening in darkness can be mediated by previous day photosynthate loads and might be a consequence of growth-related processes like dark respiration (R). To identify linkages between night-time leaf conductance (gl_night), A, R, and tree growth, we conducted an experiment in hybrid aspen saplings grown under different air relative humidity (RH) conditions and previous day irradiance level (IR_pday). Predawn leaf conductance (gl_predawn) depended on RH, IR_pday and R (P < 0.05), whereas early-morning gross A (Agross_PAR500) depended on IR_pday and gl_predawn (P < 0.001). Daytime net A was positively related to Agross_PAR500 and leaf [N] (P < 0.05). Tree diameter and height increment correlated positively with gl at the beginning and middle of the night (P < 0.05) but not before dawn. Although our results demonstrate that gl_night was related to tree growth, the relationship was not determined by R. The linkage between gl_predawn and Agross_PAR500 was modified by IR_pday, indicating that daily CO2 assimilation probably provides feedback for stomatal opening before dawn.
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Affiliation(s)
- Priit Kupper
- Institute of Ecology and Earth Sciences, University of Tartu, 51005 Tartu, Estonia; and Corresponding author.
| | - Ants Kaasik
- Institute of Ecology and Earth Sciences, University of Tartu, 51005 Tartu, Estonia
| | - Mai Kukumägi
- Institute of Ecology and Earth Sciences, University of Tartu, 51005 Tartu, Estonia
| | | | - Linda Rusalepp
- Institute of Ecology and Earth Sciences, University of Tartu, 51005 Tartu, Estonia
| | - Anu Sõber
- Institute of Ecology and Earth Sciences, University of Tartu, 51005 Tartu, Estonia
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17
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Chieppa J, Brown T, Giresi P, Juenger TE, Resco de Dios V, Tissue DT, Aspinwall MJ. Climate and stomatal traits drive covariation in nighttime stomatal conductance and daytime gas exchange rates in a widespread C 4 grass. THE NEW PHYTOLOGIST 2021; 229:2020-2034. [PMID: 33037633 DOI: 10.1111/nph.16987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/25/2020] [Indexed: 06/11/2023]
Abstract
Nighttime stomatal conductance (gsn ) varies among plant functional types and species, but factors shaping the evolution of gsn remain unclear. Examinations of intraspecific variation in gsn as a function of climate and co-varying leaf traits may provide new insight into the evolution of gsn and its adaptive significance. We grew 11 genotypes of Panicum virgatum (switchgrass) representing differing home-climates in a common garden experiment and measured nighttime and daytime leaf gas exchange, as well as stomatal density (SD) and size during early-, mid-, and late-summer. We used piecewise structural equation modelling to determine direct and indirect relationships between home-climate, gas exchange, and stomatal traits. We found no direct relationship between home-climate and gsn . However, genotypes from hotter climates possessed higher SD, which resulted in higher gsn . Across genotypes, higher gsn was associated with higher daytime stomatal conductance and net photosynthesis. Our results indicate that higher gsn may arise in genotypes from hotter climates via increased SD. High SD may provide benefits to genotypes from hotter climates through enhanced daytime transpirational cooling or by permitting maximal gas exchange when conditions are suitable. These results highlight the role of climate and trait coordination in shaping genetic differentiation in gsn .
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Affiliation(s)
- Jeff Chieppa
- Department of Biology, University of North Florida, Jacksonville, FL, 32224, USA
- School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Tia Brown
- Department of Biology, Haverford College, Haverford, PA, 19041, USA
| | - Presley Giresi
- Department of Biology, University of North Florida, Jacksonville, FL, 32224, USA
| | - Thomas E Juenger
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, 78717, USA
| | - Víctor Resco de Dios
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Michael J Aspinwall
- Department of Biology, University of North Florida, Jacksonville, FL, 32224, USA
- School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, 36849, USA
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18
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Kannenberg SA, Fiorella RP, Anderegg WRL, Monson RK, Ehleringer JR. Seasonal and diurnal trends in progressive isotope enrichment along needles in two pine species. PLANT, CELL & ENVIRONMENT 2021; 44:143-155. [PMID: 33058213 DOI: 10.1111/pce.13915] [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: 05/27/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
The Craig-Gordon type (C-G) leaf water isotope enrichment models assume a homogeneous distribution of enriched water across the leaf surface, despite observations that Δ18 O can become increasingly enriched from leaf base to tip. Datasets of this 'progressive isotope enrichment' are limited, precluding a comprehensive understanding of (a) the magnitude and variability of progressive isotope enrichment, and (b) how progressive enrichment impacts the accuracy of C-G leaf water model predictions. Here, we present observations of progressive enrichment in two conifer species that capture seasonal and diurnal variability in environmental conditions. We further examine which leaf water isotope models best capture the influence of progressive enrichment on bulk needle water Δ18 O. Observed progressive enrichment was large and equal in magnitude across both species. The magnitude of this effect fluctuated seasonally in concert with vapour pressure deficit, but was static in the face of diurnal cycles in meteorological conditions. Despite large progressive enrichment, three variants of the C-G model reasonably successfully predicted bulk needle Δ18 O. Our results thus suggest that the presence of progressive enrichment does not impact the predictive success of C-G models, and instead yields new insight regarding the physiological and anatomical mechanisms that cause progressive isotope enrichment.
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Affiliation(s)
- Steven A Kannenberg
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Richard P Fiorella
- Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, USA
| | | | - Russell K Monson
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - James R Ehleringer
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
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19
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Schoppach R, Sinclair TR, Sadok W. Sleep tight and wake-up early: nocturnal transpiration traits to increase wheat drought tolerance in a Mediterranean environment. FUNCTIONAL PLANT BIOLOGY : FPB 2020; 47:1117-1127. [PMID: 32684244 DOI: 10.1071/fp20044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 06/20/2020] [Indexed: 06/11/2023]
Abstract
In wheat, night-time transpiration rate (TRN) could amount to 14-55% of daytime transpiration rate (TR), depending on the cultivar and environment. Recent evidence suggests that TRN is much less responsive to soil drying than daytime TR, and that such 'wasteful' water losses would increase the impact of drought on yields. In contrast, other evidence indicates that pre-dawn, circadian increases in TRN may enable enhanced radiation use efficiency, resulting in increased productivity under water deficit. Until now, there have been no attempts to evaluate these seemingly conflicting hypotheses in terms of their impact on yields in any crop. Here, using the Mediterranean environment of Tunisia as a case study, we undertook a simulation modelling approach using SSM-Wheat to evaluate yield outcomes resulting from these TRN trait modifications. TRN represented 15% of daytime TR-generated yield penalties of up to 20%, and these worsened when TRN was not sensitive to soil drying TR. For the same TRN level (15%), simulating a predawn increase in TRN alleviated yield penalties, leading to yield gains of up to 25%. Overall, this work suggests that decreasing TRN but increasing pre-dawn circadian control would be a viable breeding target to increase drought tolerance in a Mediterranean environment.
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Affiliation(s)
- Rémy Schoppach
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108-6026, USA
| | - Thomas R Sinclair
- Crop Science Department, North Carolina State University, Raleigh, NC 27695-7620, USA
| | - Walid Sadok
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108-6026, USA; and Corresponding author.
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20
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Sadok W, Lopez JR, Zhang Y, Tamang BG, Muehlbauer GJ. Sheathing the blade: Significant contribution of sheaths to daytime and nighttime gas exchange in a grass crop. PLANT, CELL & ENVIRONMENT 2020; 43:1844-1861. [PMID: 32459028 DOI: 10.1111/pce.13808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/31/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
Despite representing a sizeable fraction of the canopy, very little is known about leaf sheath gas exchange in grasses. Specifically, estimates of sheath stomatal conductance, transpiration and photosynthesis along with their responses to light, CO2 and vapour pressure deficit (VPD) are unknown. Furthermore, the anatomical basis of these responses is poorly documented. Here, using barley as a model system, and combining leaf-level gas exchange, whole-plant gravimetric measurements, transpiration inhibitors, anatomical observations, and biophysical modelling, we found that sheath and blade stomatal conductance and transpiration were similar, especially at low light, in addition to being genotypically variable. Thanks to high abaxial stomata densities and surface areas nearly half those of the blades, sheaths accounted for up to 17% of the daily whole-plant water use, which -surprisingly- increased to 45% during the nighttime. Sheath photosynthesis was on average 17-25% that of the blade and was associated with lower water use efficiency. Finally, sheaths responded differently to the environment, exhibiting a lack of response to CO2 but a strong sensitivity to VPD. Overall, these results suggest a key involvement of sheaths in feedback loops between canopy architecture and gas exchange with potentially significant implications on adaptation to current and future climates in grasses.
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Affiliation(s)
- Walid Sadok
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota, USA
| | - Jose R Lopez
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota, USA
| | - Yangyang Zhang
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota, USA
- Department of Grassland Science, China Agricultural University, Beijing, China
| | - Bishal G Tamang
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota, USA
| | - Gary J Muehlbauer
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota, USA
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21
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Sadok W, Jagadish SVK. The Hidden Costs of Nighttime Warming on Yields. TRENDS IN PLANT SCIENCE 2020; 25:644-651. [PMID: 32526169 DOI: 10.1016/j.tplants.2020.02.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 05/18/2023]
Abstract
Nighttime warming poses a threat to global food security as it is driving yield declines worldwide, but our understanding of the physiological basis of this phenomenon remains very limited. Furthermore, it is often assumed that such declines are driven solely by increases in nighttime temperature (TNight). Here we argue that, in addition to temperature, increases in nighttime evaporative demand may 'conspire' to penalize yields and end-use quality traits. We propose an ecophysiological framework outlining the possible mechanistic basis of such declines in yield and quality. We suggest ways to use the proposed framework as a guide to future efforts aimed at alleviating productivity losses by integrating crop ecophysiology with modeling, breeding, and management.
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Affiliation(s)
- Walid Sadok
- Department of Agronomy and Plant Genetics, University of Minnesota Twin Cities, MN, USA.
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22
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Identification of suites of traits that explains drought resistance and phenological patterns of plants in a semi-arid grassland community. Oecologia 2020; 192:55-66. [PMID: 31932921 DOI: 10.1007/s00442-019-04567-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 11/22/2019] [Indexed: 11/25/2022]
Abstract
Grassland ecosystems are comprised of plants that occupy a wide array of phenological niches and vary considerably in their ability to resist the stress of seasonal soil-water deficits. Yet, the link between plant drought resistance and phenology remains unclear in perennial grassland ecosystems. To evaluate the role of soil water availability and plant drought tolerance in driving phenology, we measured leaf hydraulic conductance (Ksat), resistance to hydraulic failure (P50), leaf gas exchange, plant and soil water stable isotope ratios (δ18O), and several phenology metrics on ten perennial herbaceous species in mixed-grass prairie. The interaction between P50 and δ18O of xylem water explained 67% of differences in phenology, with lower P50 values associated with later season activity, but only among shallow-rooted species. In addition, stomatal control and high water-use efficiency also contributed to the late flowering and late senescence strategies of plants that had low P50 values and relied upon shallow soil water. Alternatively, plants with deeper roots did not possess drought-tolerant leaves, but had high hydraulic efficiency, contributing to their ability to efficiently move water longer distances while maintaining leaf water potential at relatively high values. The suites of traits that characterize these contrasting strategies provide a mechanistic link between phenology and plant-water relations; thus, these traits could help predict grassland community responses to changes in water availability, both temporally and vertically within the soil profile.
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23
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Resco de Dios V, Chowdhury FI, Granda E, Yao Y, Tissue DT. Assessing the potential functions of nocturnal stomatal conductance in C 3 and C 4 plants. THE NEW PHYTOLOGIST 2019; 223:1696-1706. [PMID: 31055839 DOI: 10.1111/nph.15881] [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: 03/27/2019] [Accepted: 04/24/2019] [Indexed: 05/16/2023]
Abstract
Nocturnal stomatal conductance contributes to water loss at night without carbon gain in C3 or C4 plants because photosynthesis does not occur in the dark. The functional relevance of nocturnal conductance thus remains an unresolved conundrum. Here, we review and re-analyse previously published datasets on nocturnal conductance (gn ) globally (176 species) to synthesize our current understanding on its potential biological function and to identify remaining research gaps. We found that gn was positively correlated with relative growth rate, which is compatible with the postulate that circadian-driven nocturnal conductance enhances predawn stomatal conductance, thereby priming stomata for photosynthesis in early daylight. The variation in gn across plant species and functional types was not consistent with the hypotheses that the main function of gn is to: remove excess CO2, which might limit growth; enhance oxygen delivery to the functional sapwood; enhance nutrient supply; or that gn is due to stomatal leakiness. We suggest further study regarding the potential of gn to be an important functional and ecological trait influencing competitive outcomes and we outline a research programme to achieve that objective.
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Affiliation(s)
- Víctor Resco de Dios
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
- Department of Crop and Forest Sciences & Agrotecnio Center, Universitat de Lleida, Lleida, 25198, Spain
| | - Faqrul I Chowdhury
- Master Course Mediterranean Forestry and Natural Resources Management, Universitat de Lleida, Lleida, 25198, Spain
| | - Elena Granda
- Department of Crop and Forest Sciences & Agrotecnio Center, Universitat de Lleida, Lleida, 25198, Spain
| | - Yinan Yao
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Richmond, NSW, 2753, Australia
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