1
|
Pichaco J, Manandhar A, McAdam SAM. Mechanical advantage makes stomatal opening speed a function of evaporative demand. PLANT PHYSIOLOGY 2024; 195:370-377. [PMID: 38217870 DOI: 10.1093/plphys/kiae023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/15/2024]
Abstract
Stomatal opening in the light, observed in nearly all vascular land plants, is essential for providing access to atmospheric CO2 for photosynthesis. The speed of stomatal opening in the light is critical for maximizing carbon gain in environments in which light intensity changes, yet we have little understanding of how other environmental signals, particularly evaporative demand driven by vapor pressure deficit (VPD) influences the kinetics of this response. In angiosperms, and some fern species from the family Marsileaceae, a mechanical interaction between the guard cells and the epidermal cells determines the aperture of the pore. Here, we examine whether this mechanical interaction influences the speed of stomatal opening in the light. To test this, we investigated the speed of stomatal opening in response to light across a range of VPDs in seven plant species spanning the evolutionary diversity of guard cell and epidermal cell mechanical interactions. We found that stomatal opening speed is a function of evaporative demand in angiosperm species and Marsilea, which have guard cell and epidermal cell mechanical interactions. Stomatal opening speeds did not change across a range of VPD in species of gymnosperm and fern, which do not have guard cell mechanical interactions with the epidermis. We find that guard cell and epidermal cell mechanical interactions may play a key role in regulating stomatal responsiveness to light. These results provide valuable insight into the adaptive relevance of mechanical advantage.
Collapse
Affiliation(s)
- Javier Pichaco
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Avenida Reina Mercedes 10, 41012 Seville, Spain
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| | - Anju Manandhar
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| |
Collapse
|
2
|
Binstock BR, Manandhar A, McAdam SAM. Characterizing the breakpoint of stomatal response to vapor pressure deficit in an angiosperm. PLANT PHYSIOLOGY 2024; 194:732-740. [PMID: 37850913 DOI: 10.1093/plphys/kiad560] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/21/2023] [Accepted: 10/05/2023] [Indexed: 10/19/2023]
Abstract
Vapor pressure difference between the leaf and atmosphere (VPD) is the most important regulator of daytime transpiration, yet the mechanism driving stomatal responses to an increase in VPD in angiosperms remains unresolved. Here, we sought to characterize the mechanism driving stomatal closure at high VPD in an angiosperm species, particularly testing whether abscisic acid (ABA) biosynthesis could explain the observation of a trigger point for stomatal sensitivity to an increase in VPD. We tracked leaf gas exchange and modeled leaf water potential (Ψl) in leaves exposed to a range of step-increases in VPD in the herbaceous species Senecio minimus Poir. (Asteraceae). We found that mild increases in VPD in this species did not induce stomatal closure because modeled Ψl did not decline below a threshold close to turgor loss point (Ψtlp), but when leaves were exposed to a large increase in VPD, stomata closed as modeled Ψl declined below Ψtlp. Leaf ABA levels were higher in leaves exposed to a step-increase in VPD that caused Ψl to transiently decline below Ψtlp and in which stomata closed compared with leaves in which stomata did not close. We conclude that the stomata of S. minimus are insensitive to VPD until Ψl declines to a threshold that triggers the biosynthesis of ABA and that this mechanism might be common to angiosperms.
Collapse
Affiliation(s)
- Benjamin R Binstock
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| | - Anju Manandhar
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| |
Collapse
|
3
|
Blatt MR, Jezek M, Lew VL, Hills A. What can mechanistic models tell us about guard cells, photosynthesis, and water use efficiency? TRENDS IN PLANT SCIENCE 2022; 27:166-179. [PMID: 34565672 DOI: 10.1016/j.tplants.2021.08.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/19/2021] [Accepted: 08/26/2021] [Indexed: 06/13/2023]
Abstract
Stomatal pores facilitate gaseous exchange between the inner air spaces of the leaf and the atmosphere. The pores open to enable CO2 entry for photosynthesis and close to reduce transpirational water loss. How stomata respond to the environment has long attracted interest in modeling as a tool to understand the consequences for the plant and for the ecosystem. Models that focus on stomatal conductance for gas exchange make intuitive sense, but such models need also to connect with the mechanics of the guard cells that regulate pore aperture if we are to understand the 'decisions made' by stomata, their impacts on the plant and on the global environment.
Collapse
Affiliation(s)
- Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Bower Building, Glasgow G12 8QQ, UK.
| | - Mareike Jezek
- Journal of Experimental Botany, Lancaster University, Lancaster LA1 4YW, UK
| | - Virgilio L Lew
- The Physiological Laboratory, University of Cambridge, Cambridge CB2 3EG, UK
| | - Adrian Hills
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Bower Building, Glasgow G12 8QQ, UK
| |
Collapse
|
4
|
Abscisic Acid Biosynthesis and Signaling in Plants: Key Targets to Improve Water Use Efficiency and Drought Tolerance. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10186322] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The observation of a much-improved fitness of wild-type plants over abscisic acid (ABA)-deficient mutants during drought has led researchers from all over to world to perform experiments aiming at a better understanding of how this hormone modulates the physiology of plants under water-limited conditions. More recently, several promising approaches manipulating ABA biosynthesis and signaling have been explored to improve water use efficiency and confer drought tolerance to major crop species. Here, we review recent progress made in the last decade on (i) ABA biosynthesis, (ii) the roles of ABA on plant-water relations and on primary and secondary metabolisms during drought, and (iii) the regulation of ABA levels and perception to improve water use efficiency and drought tolerance in crop species.
Collapse
|
5
|
Cardoso AA, Visel D, Kane CN, Batz TA, García Sánchez C, Kaack L, Lamarque LJ, Wagner Y, King A, Torres-Ruiz JM, Corso D, Burlett R, Badel E, Cochard H, Delzon S, Jansen S, McAdam SAM. Drought-induced lacuna formation in the stem causes hydraulic conductance to decline before xylem embolism in Selaginella. THE NEW PHYTOLOGIST 2020; 227:1804-1817. [PMID: 32386326 DOI: 10.1111/nph.16649] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 04/22/2020] [Indexed: 05/25/2023]
Abstract
Lycophytes are the earliest diverging extant lineage of vascular plants, sister to all other vascular plants. Given that most species are adapted to ever-wet environments, it has been hypothesized that lycophytes, and by extension the common ancestor of all vascular plants, have few adaptations to drought. We investigated the responses to drought of key fitness-related traits such as stomatal regulation, shoot hydraulic conductance (Kshoot ) and stem xylem embolism resistance in Selaginella haematodes and S. pulcherrima, both native to tropical understory. During drought stomata in both species were found to close before declines in Kshoot , with a 50% loss of Kshoot occurring at -1.7 and -2.5 MPa in S. haematodes and S. pulcherrima, respectively. Direct observational methods revealed that the xylem of both species was resistant to embolism formation, with 50% of embolized xylem area occurring at -3.0 and -4.6 MPa in S. haematodes and S. pulcherrima, respectively. X-ray microcomputed tomography images of stems revealed that the decline in Kshoot occurred with the formation of an air-filled lacuna, disconnecting the central vascular cylinder from the cortex. We propose that embolism-resistant xylem and large capacitance, provided by collapsing inner cortical cells, is essential for Selaginella survival during water deficit.
Collapse
Affiliation(s)
- Amanda A Cardoso
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Dominik Visel
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Cade N Kane
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Timothy A Batz
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Clara García Sánchez
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | | | - Yael Wagner
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Andrew King
- Synchrotron Source Optimisée de Lumière d'Energie Intermédiaire du LURE, L'Orme de Merisiers, Saint Aubin-BP48, Gif-sur-Yvette Cedex, France
| | - José M Torres-Ruiz
- INRAE, PIAF, Université Clermont-Auvergne, Clermont-Ferrand, 63000, France
| | - Déborah Corso
- INRAE, BIOGECO, University of Bordeaux, Pessac, 33615, France
| | - Régis Burlett
- INRAE, BIOGECO, University of Bordeaux, Pessac, 33615, France
| | - Eric Badel
- INRAE, PIAF, Université Clermont-Auvergne, Clermont-Ferrand, 63000, France
| | - Hervé Cochard
- INRAE, PIAF, Université Clermont-Auvergne, Clermont-Ferrand, 63000, France
| | - Sylvain Delzon
- INRAE, BIOGECO, University of Bordeaux, Pessac, 33615, France
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| |
Collapse
|
6
|
Deans RM, Brodribb TJ, Busch FA, Farquhar GD. Optimization can provide the fundamental link between leaf photosynthesis, gas exchange and water relations. NATURE PLANTS 2020; 6:1116-1125. [PMID: 32895529 DOI: 10.1038/s41477-020-00760-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 07/28/2020] [Indexed: 05/12/2023]
Abstract
Tight coordination in the photosynthetic, gas exchange and water supply capacities of leaves is a globally conserved trend across land plants. Strong selective constraints on leaf carbon gain create the opportunity to use quantitative optimization theory to understand the connected evolution of leaf photosynthesis and water relations. We developed an analytical optimization model that maximizes the long-term rate of leaf carbon gain, given the carbon costs in building and maintaining stomata, leaf hydraulics and osmotic pressure. Our model demonstrates that selection for optimal gain should drive coordination between key photosynthetic, gas exchange and water relations traits. It also provides predictions of adaptation to drought and the relative costs of key leaf functional traits. Our results show that optimization in terms of carbon gain, given the carbon costs of physiological traits, successfully unites leaf photosynthesis and water relations and provides a quantitative framework to consider leaf functional evolution and adaptation.
Collapse
Affiliation(s)
- Ross M Deans
- ARC Centre of Excellence in Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Florian A Busch
- ARC Centre of Excellence in Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Graham D Farquhar
- ARC Centre of Excellence in Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia.
| |
Collapse
|
7
|
Klejchová M, Hills A, Blatt MR. Predicting the unexpected in stomatal gas exchange: not just an open-and-shut case. Biochem Soc Trans 2020; 48:881-889. [PMID: 32453378 PMCID: PMC7329339 DOI: 10.1042/bst20190632] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/01/2020] [Accepted: 05/04/2020] [Indexed: 12/22/2022]
Abstract
Plant membrane transport, like transport across all eukaryotic membranes, is highly non-linear and leads to interactions with characteristics so complex that they defy intuitive understanding. The physiological behaviour of stomatal guard cells is a case in point in which, for example, mutations expected to influence stomatal closing have profound effects on stomatal opening and manipulating transport across the vacuolar membrane affects the plasma membrane. Quantitative mathematical modelling is an essential tool in these circumstances, both to integrate the knowledge of each transport process and to understand the consequences of their manipulation in vivo. Here, we outline the OnGuard modelling environment and its use as a guide to predicting the emergent properties arising from the interactions between non-linear transport processes. We summarise some of the recent insights arising from OnGuard, demonstrate its utility in interpreting stomatal behaviour, and suggest ways in which the OnGuard environment may facilitate 'reverse-engineering' of stomata to improve water use efficiency and carbon assimilation.
Collapse
Affiliation(s)
- Martina Klejchová
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Bower Building, Glasgow G12 8QQ, U.K
| | - Adrian Hills
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Bower Building, Glasgow G12 8QQ, U.K
| | - Michael R. Blatt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Bower Building, Glasgow G12 8QQ, U.K
| |
Collapse
|
8
|
McAdam SAM, Sussmilch FC. The evolving role of abscisic acid in cell function and plant development over geological time. Semin Cell Dev Biol 2020; 109:39-45. [PMID: 32571626 DOI: 10.1016/j.semcdb.2020.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 01/03/2023]
Abstract
Abscisic acid (ABA) is found in a wide diversity of organisms, yet we know most about the hormonal action of this compound in the ecologically dominant and economically important angiosperms. In angiosperms, ABA regulates a suite of critical responses from desiccation tolerance through to seed dormancy and stomatal closure. Work exploring the function of key genes in the ABA signalling pathway of angiosperms has revealed that this signal transduction pathway is ancient, yet considerable change in the physiological roles of this hormone have occurred over geological time. With recent advances in our capacity to characterise gene function in non-angiosperms we are on the cusp of revealing the origins of this critical hormonal signalling pathway in plants, and understanding how a simple hormone may have shaped land plant diversity, ecology and adaptation over the past 500 million years.
Collapse
Affiliation(s)
- Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.
| | - Frances C Sussmilch
- School of Natural Sciences, University of Tasmania, Sandy Bay, TAS, 7005, Australia
| |
Collapse
|
9
|
Rodriguez-Dominguez CM, Brodribb TJ. Declining root water transport drives stomatal closure in olive under moderate water stress. THE NEW PHYTOLOGIST 2020; 225:126-134. [PMID: 31498457 DOI: 10.1111/nph.16177] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 09/01/2019] [Indexed: 05/24/2023]
Abstract
Efficient water transport from soil to leaves sustains stomatal opening and steady-state photosynthesis. The aboveground portion of this pathway is well-described, yet the roots and their connection with the soil are still poorly understood due to technical limitations. Here we used a novel rehydration technique to investigate changes in the hydraulic pathway between roots and soil and within the plant body as individual olive plants were subjected to a range of water stresses. Whole root hydraulic resistance (including the radial pathway from xylem to the soil-root interface) constituted 81% of the whole-plant resistance in unstressed plants, increasing to > 95% under a moderate level of water stress. The decline in this whole root hydraulic conductance occurred in parallel with stomatal closure and contributed significantly to the reduction in canopy conductance according to a hydraulic model. Our results demonstrate that losses in root hydraulic conductance, mainly due to a disconnection from the soil during moderate water stress in olive plants, are profound and sufficient to induce stomatal closure before cavitation occurs. Future studies will determine whether this core regulatory role of root hydraulics exists more generally among diverse plant species.
Collapse
Affiliation(s)
- Celia M Rodriguez-Dominguez
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Avenida Reina Mercedes, 10, 41012, Sevilla, Spain
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| |
Collapse
|
10
|
Buckley TN. How do stomata respond to water status? THE NEW PHYTOLOGIST 2019; 224:21-36. [PMID: 31069803 DOI: 10.1111/nph.15899] [Citation(s) in RCA: 195] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/25/2019] [Indexed: 05/20/2023]
Abstract
Stomatal responses to humidity, soil moisture and other factors that influence plant water status are critical drivers of photosynthesis, productivity, water yield, ecohydrology and climate forcing, yet we still lack a thorough mechanistic understanding of these responses. Here I review historical and recent advances in stomatal water relations. Clear evidence now implicates a metabolically mediated response to leaf water status ('hydroactive feedback') in stomatal responses to evaporative demand and soil drought, possibly involving abscisic acid production in leaves. Other hypothetical mechanisms involving vapor and heat transport within leaves may contribute to humidity, light and temperature responses, but require further theoretical clarification and experimental validation. Variation and dynamics in hydraulic conductance, particularly within leaves, may contribute to water status responses. Continuing research to fully resolve mechanisms of stomatal responses to water status should focus on several areas: validating and quantifying the mechanism of leaf-based hydroactive feedback, identifying where in leaves water status is actively sensed, clarifying the role of leaf vapor and energy transport in humidity and temperature responses, and verifying foundational but minimally replicated results of stomatal hydromechanics across species. Clarity on these matters promises to deliver modelers with a tractable and reliable mechanistic model of stomatal responses to water status.
Collapse
Affiliation(s)
- Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
| |
Collapse
|
11
|
Cardoso AA, Randall JM, McAdam SAM. Hydraulics Regulate Stomatal Responses to Changes in Leaf Water Status in the Fern Athyrium filix- femina. PLANT PHYSIOLOGY 2019; 179:533-543. [PMID: 30538169 PMCID: PMC6426430 DOI: 10.1104/pp.18.01412] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 12/03/2018] [Indexed: 05/25/2023]
Abstract
Stomatal responses to changes in leaf water status are important for the diurnal regulation of gas exchange and the survival of plants during drought. These stomatal responses in angiosperm species are well characterized, yet in species of nonseed plants, an ongoing debate surrounds the role of metabolism, particularly the role of the hormone abscisic acid (ABA), in functionally regulating stomatal responses to changes in leaf water status. Here, we measured the stomatal response to changes in vapor pressure difference (VPD) in two natural forms of the fern species Athyrium filix-femina, recently suggested to have stomata that are regulated by ABA. The two forms measured had considerable differences in key hydraulic traits, including leaf hydraulic conductance and capacitance, as well as the kinetics of stomatal response to changes in VPD. In both forms, the stomatal responses to VPD could be accurately predicted by a dynamic, mechanistic model that assumes guard cell turgor changes in concert with leaf turgor in the light, and not via metabolic processes including the level of ABA. During drought, endogenous ABA did not play a role in stomatal closure, and exogenous ABA applied to live, intact leaves did not induce stomatal closure. Our results indicate that functional stomatal responses to changes in leaf water status in ferns are regulated by leaf hydraulics and not metabolism. With ferns being sister to seed plants, this result has implications for the evolutionary reconstruction of functional stomatal responses across vascular land plant lineages.
Collapse
Affiliation(s)
- Amanda A Cardoso
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Joshua M Randall
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| |
Collapse
|
12
|
Peccoux A, Loveys B, Zhu J, Gambetta GA, Delrot S, Vivin P, Schultz HR, Ollat N, Dai Z. Dissecting the rootstock control of scion transpiration using model-assisted analyses in grapevine. TREE PHYSIOLOGY 2018; 38:1026-1040. [PMID: 29228360 DOI: 10.1093/treephys/tpx153] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Accepted: 10/31/2017] [Indexed: 05/06/2023]
Abstract
How rootstocks contribute to the control of scion transpiration under drought is poorly understood. We investigated the role of root characteristics, hydraulic conductance and chemical signals (abscisic acid, ABA) in the response of stomatal conductance (gs) and transpiration (E) to drought in Cabernet Sauvignon (Vitis vinifera) grafted onto drought-sensitive (Vitis riparia) and drought-tolerant (Vitis berlandieri × Vitis rupestris 110R) rootstocks. All combinations showed a concomitant reduction in gs and E, and an increase in xylem sap ABA concentration during the drought cycle. Cabernet Sauvignon grafted onto 110R exhibited higher gs and E under well-watered and moderate water deficit, but all combinations converged as water deficit increased. These results were integrated into three permutations of a whole-plant transpiration model that couples both chemical (i.e., ABA) and hydraulic signals in the modelling of stomatal control. Model comparisons revealed that both hydraulic and chemical signals were important for rootstock-specific stomatal regulation. Moreover, model parameter comparison and sensitivity analysis highlighted two major parameters differentiating the rootstocks: (i) ABA biosynthetic activity and (ii) the hydraulic conductance between the rhizosphere and soil-root interface determined by root system architecture. These differences in root architecture, specifically a higher root length area in 110R, likely explain its higher E and gs observed at low and moderate water deficit.
Collapse
Affiliation(s)
- Anthony Peccoux
- EGFV, Bordeaux Sciences Agro, CNRS, INRA, ISVV, Université de Bordeaux, Villenave d'Ornon, France
- Hochschule Geisenheim University, von-Lade-Straße 1, Geisenheim, Germany
| | - Brian Loveys
- CSIRO Plant Industry, Glen Osmond, SA, Australia
| | - Junqi Zhu
- EGFV, Bordeaux Sciences Agro, CNRS, INRA, ISVV, Université de Bordeaux, Villenave d'Ornon, France
| | - Gregory A Gambetta
- EGFV, Bordeaux Sciences Agro, CNRS, INRA, ISVV, Université de Bordeaux, Villenave d'Ornon, France
| | - Serge Delrot
- EGFV, Bordeaux Sciences Agro, CNRS, INRA, ISVV, Université de Bordeaux, Villenave d'Ornon, France
| | - Philippe Vivin
- EGFV, Bordeaux Sciences Agro, CNRS, INRA, ISVV, Université de Bordeaux, Villenave d'Ornon, France
| | - Hans R Schultz
- Hochschule Geisenheim University, von-Lade-Straße 1, Geisenheim, Germany
| | - Nathalie Ollat
- EGFV, Bordeaux Sciences Agro, CNRS, INRA, ISVV, Université de Bordeaux, Villenave d'Ornon, France
| | - Zhanwu Dai
- EGFV, Bordeaux Sciences Agro, CNRS, INRA, ISVV, Université de Bordeaux, Villenave d'Ornon, France
| |
Collapse
|
13
|
McAdam SAM, Brodribb TJ. Mesophyll Cells Are the Main Site of Abscisic Acid Biosynthesis in Water-Stressed Leaves. PLANT PHYSIOLOGY 2018; 177:911-917. [PMID: 29735726 PMCID: PMC6052997 DOI: 10.1104/pp.17.01829] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 04/25/2018] [Indexed: 05/05/2023]
Abstract
The hormone abscisic acid (ABA) plays a critical role in enhancing plant survival during water deficit. Recent molecular evidence suggests that ABA is synthesized in the phloem companion cells and guard cells. However, the nature of cell turgor and water status in these two cell types cannot easily account for the rapid, water status-triggered ABA biosynthesis observed in leaves. Here, we utilize the unique foliar anatomies of an angiosperm (Hakea lissosperma) and four conifer species (Saxegothaea conspicua, Podocarpus latifolius, Cephalotaxus harringtonii, and Amentotaxus formosana) in which the mesophyll can be isolated from the vascular tissue to identify the main site of ABA biosynthesis in water-stressed leaves. In all five species tested, considerable ABA biosynthesis occurred in mesophyll tissue that had been separated from vascular tissue. In addition, the removal of the epidermis from the mesophyll in two conifer species had no impact on the observed increase in ABA levels under water deficit. Our results suggest that mesophyll cells are the predominant location of water deficit-triggered ABA biosynthesis in the leaf.
Collapse
Affiliation(s)
- Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania 7005, Australia
| |
Collapse
|
14
|
Affiliation(s)
- Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| |
Collapse
|
15
|
|
16
|
Brodribb TJ, McAdam SAM. Evolution of the Stomatal Regulation of Plant Water Content. PLANT PHYSIOLOGY 2017; 174:639-649. [PMID: 28404725 PMCID: PMC5462025 DOI: 10.1104/pp.17.00078] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 04/11/2017] [Indexed: 05/19/2023]
Abstract
Changes in the function of stomata from the earliest bryophytes to derived angiosperms are examined.
Collapse
Affiliation(s)
- Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart TAS 7001, Australia
| | - Scott A M McAdam
- School of Biological Sciences, University of Tasmania, Hobart TAS 7001, Australia
| |
Collapse
|