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Mercado-Reyes JA, Pereira TS, Manandhar A, Rimer IM, McAdam SAM. Extreme drought can deactivate ABA biosynthesis in embolism-resistant species. PLANT, CELL & ENVIRONMENT 2024; 47:497-510. [PMID: 37905689 DOI: 10.1111/pce.14754] [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: 03/25/2022] [Revised: 08/24/2023] [Accepted: 10/18/2023] [Indexed: 11/02/2023]
Abstract
The phytohormone abscisic acid (ABA) is synthesised by plants during drought to close stomata and regulate desiccation tolerance pathways. Conifers and some angiosperms with embolism-resistant xylem show a peaking-type (p-type) response in ABA levels, in which ABA levels increase early in drought then decrease as drought progresses, declining to pre-stressed levels. The mechanism behind this dynamic remains unknown. Here, we sought to characterise the mechanism driving p-type ABA dynamics in the conifer Callitris rhomboidea and the highly drought-resistant angiosperm Umbellularia californica. We measured leaf water potentials (Ψl ), stomatal conductance, ABA, conjugates and phaseic acid (PA) levels in potted plants during a prolonged but non-fatal drought. Both species displayed a p-type ABA dynamic during prolonged drought. In branches collected before and after the peak in endogenous ABA levels in planta, that were rehydrated overnight and then bench dried, ABA biosynthesis was deactivated beyond leaf turgor loss point. Considerable conversion of ABA to conjugates was found to occur during drought, but not catabolism to PA. The mechanism driving the decline in ABA levels in p-type species may be conserved across embolism-resistant seed plants and is mediated by sustained conjugation of ABA and the deactivation of ABA accumulation as Ψl becomes more negative than turgor loss.
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Affiliation(s)
- Joel A Mercado-Reyes
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA
| | - Talitha Soares Pereira
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA
| | - Anju Manandhar
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA
| | - Ian M Rimer
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA
| | - Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA
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2
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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: 0] [Impact Index Per Article: 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.
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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
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3
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Wuyun T, Niinemets Ü, Hõrak H. Species-specific stomatal ABA responses in juvenile ferns grown from spores. THE NEW PHYTOLOGIST 2023; 240:1722-1728. [PMID: 37635267 DOI: 10.1111/nph.19215] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/26/2023] [Indexed: 08/29/2023]
Affiliation(s)
- Tana Wuyun
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51006, Tartu, Estonia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51006, Tartu, Estonia
| | - Hanna Hõrak
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51006, Tartu, Estonia
- Institute of Technology, University of Tartu, Nooruse 1, 50411, Tartu, Estonia
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Liu S, Zenda T, Tian Z, Huang Z. Metabolic pathways engineering for drought or/and heat tolerance in cereals. FRONTIERS IN PLANT SCIENCE 2023; 14:1111875. [PMID: 37810398 PMCID: PMC10557149 DOI: 10.3389/fpls.2023.1111875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 09/04/2023] [Indexed: 10/10/2023]
Abstract
Drought (D) and heat (H) are the two major abiotic stresses hindering cereal crop growth and productivity, either singly or in combination (D/+H), by imposing various negative impacts on plant physiological and biochemical processes. Consequently, this decreases overall cereal crop production and impacts global food availability and human nutrition. To achieve global food and nutrition security vis-a-vis global climate change, deployment of new strategies for enhancing crop D/+H stress tolerance and higher nutritive value in cereals is imperative. This depends on first gaining a mechanistic understanding of the mechanisms underlying D/+H stress response. Meanwhile, functional genomics has revealed several stress-related genes that have been successfully used in target-gene approach to generate stress-tolerant cultivars and sustain crop productivity over the past decades. However, the fast-changing climate, coupled with the complexity and multigenic nature of D/+H tolerance suggest that single-gene/trait targeting may not suffice in improving such traits. Hence, in this review-cum-perspective, we advance that targeted multiple-gene or metabolic pathway manipulation could represent the most effective approach for improving D/+H stress tolerance. First, we highlight the impact of D/+H stress on cereal crops, and the elaborate plant physiological and molecular responses. We then discuss how key primary metabolism- and secondary metabolism-related metabolic pathways, including carbon metabolism, starch metabolism, phenylpropanoid biosynthesis, γ-aminobutyric acid (GABA) biosynthesis, and phytohormone biosynthesis and signaling can be modified using modern molecular biotechnology approaches such as CRISPR-Cas9 system and synthetic biology (Synbio) to enhance D/+H tolerance in cereal crops. Understandably, several bottlenecks hinder metabolic pathway modification, including those related to feedback regulation, gene functional annotation, complex crosstalk between pathways, and metabolomics data and spatiotemporal gene expressions analyses. Nonetheless, recent advances in molecular biotechnology, genome-editing, single-cell metabolomics, and data annotation and analysis approaches, when integrated, offer unprecedented opportunities for pathway engineering for enhancing crop D/+H stress tolerance and improved yield. Especially, Synbio-based strategies will accelerate the development of climate resilient and nutrient-dense cereals, critical for achieving global food security and combating malnutrition.
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Affiliation(s)
- Songtao Liu
- Hebei Key Laboratory of Quality & Safety Analysis-Testing for Agro-Products and Food, Hebei North University, Zhangjiakou, China
| | - Tinashe Zenda
- State Key Laboratory of North China Crop Improvement and Regulation, Hebei Agricultural University, Baoding, China
| | - Zaimin Tian
- Hebei Key Laboratory of Quality & Safety Analysis-Testing for Agro-Products and Food, Hebei North University, Zhangjiakou, China
| | - Zhihong Huang
- Hebei Key Laboratory of Quality & Safety Analysis-Testing for Agro-Products and Food, Hebei North University, Zhangjiakou, China
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Koehler T, Wankmüller FJP, Sadok W, Carminati A. Transpiration response to soil drying versus increasing vapor pressure deficit in crops: physical and physiological mechanisms and key plant traits. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4789-4807. [PMID: 37354081 PMCID: PMC10474596 DOI: 10.1093/jxb/erad221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 06/07/2023] [Indexed: 06/26/2023]
Abstract
The water deficit experienced by crops is a function of atmospheric water demand (vapor pressure deficit) and soil water supply over the whole crop cycle. We summarize typical transpiration response patterns to soil and atmospheric drying and the sensitivity to plant hydraulic traits. We explain the transpiration response patterns using a soil-plant hydraulic framework. In both cases of drying, stomatal closure is triggered by limitations in soil-plant hydraulic conductance. However, traits impacting the transpiration response differ between the two drying processes and act at different time scales. A low plant hydraulic conductance triggers an earlier restriction in transpiration during increasing vapor pressure deficit. During soil drying, the impact of the plant hydraulic conductance is less obvious. It is rather a decrease in the belowground hydraulic conductance (related to soil hydraulic properties and root length density) that is involved in transpiration down-regulation. The transpiration response to increasing vapor pressure deficit has a daily time scale. In the case of soil drying, it acts on a seasonal scale. Varieties that are conservative in water use on a daily scale may not be conservative over longer time scales (e.g. during soil drying). This potential independence of strategies needs to be considered in environment-specific breeding for yield-based drought tolerance.
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Affiliation(s)
- Tina Koehler
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Fabian J P Wankmüller
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
| | - Walid Sadok
- Agronomy and Plant Genetics, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, Twin Cities, MN, USA
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
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Eyland D, Gambart C, Swennen R, Carpentier S. Unravelling the diversity in water usage among wild banana species in response to vapour pressure deficit. FRONTIERS IN PLANT SCIENCE 2023; 14:1068191. [PMID: 37670859 PMCID: PMC10475999 DOI: 10.3389/fpls.2023.1068191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 08/03/2023] [Indexed: 09/07/2023]
Abstract
The rise in global temperature is not only affecting plant functioning directly, but is also increasing air vapour pressure deficit (VPD). The yield of banana is heavily affected by water deficit but so far breeding programs have never addressed the issue of water deficit caused by high VPD. A reduction in transpiration at high VPD has been suggested as a key drought tolerance breeding trait to avoid excessive water loss, hydraulic failure and to increase water use efficiency. In this study, stomatal and transpiration responses under increasing VPD at the leaf and whole-plant level of 8 wild banana (sub)species were evaluated, displaying significant differences in stomatal reactivity. Three different phenotypic groups were identified under increasing VPD. While (sub)species of group III maintained high transpiration rates under increasing VPD, M. acuminata ssp. errans (group I), M. acuminata ssp. zebrina (group II) and M. balbisiana (group II) showed the highest transpiration rate limitations to increasing VPD. In contrast to group I, group II only showed strong reductions at high VPD levels, limiting the cost of reduced photosynthesis and strongly increasing their water use efficiency. M. acuminata ssp. zebrina and M. balbisiana thus show the most favourable responses. This study provides a basis for the identification of potential parent material in gene banks for breeding future-proof bananas that cope better with lack of water.
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Affiliation(s)
- David Eyland
- Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, KU Leuven, Heverlee, Belgium
| | - Clara Gambart
- Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, KU Leuven, Heverlee, Belgium
| | - Rony Swennen
- Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, KU Leuven, Heverlee, Belgium
- International Institute of Tropical Agriculture, Banana Breeding, Kampala, Uganda
| | - Sebastien Carpentier
- Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, KU Leuven, Heverlee, Belgium
- Bioversity International, Biodiversity for Food and Agriculture, Leuven, Belgium
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7
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Mandour H, Khazaei H, Stoddard FL, Dodd IC. Identifying physiological and genetic determinants of faba bean transpiration response to evaporative demand. ANNALS OF BOTANY 2023; 131:533-544. [PMID: 36655613 PMCID: PMC10072112 DOI: 10.1093/aob/mcad006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND AIMS Limiting maximum transpiration rate (TR) under high vapour pressure deficit (VPD) works as a water conservation strategy. While some breeding programmes have incorporated this trait into some crops to boost yields in water-limited environments, its underlying physiological mechanisms and genetic regulation remain unknown for faba bean (Vicia faba). Thus, we aimed to identify genetic variation in the TR response to VPD in a population of faba bean recombinant inbred lines (RILs) derived from two parental lines with contrasting water use (Mélodie/2 and ILB 938/2). METHODS Plants were grown in well-watered soil in a climate-controlled glasshouse with diurnally fluctuating VPD and light conditions. Whole plant transpiration was measured in a gas exchange chamber that tightly regulated VPD around the shoot under constant light, while whole-plant hydraulic conductance and its components (root and stem hydraulic conductance) were calculated from dividing TR by water potential gradients measured with a pressure chamber. KEY RESULTS Although TR of Mélodie/2 increased linearly with VPD, ILB 938/2 limited its TR above 2.0 kPa. Nevertheless, Mélodie/2 had a higher leaf water potential than ILB 938/2 at both low (1.0 kPa) and high (3.2 kPa) VPD. Almost 90 % of the RILs limited their TR at high VPD with a break-point (BP) range of 1.5-3.0 kPa and about 10 % had a linear TR response to VPD. Thirteen genomic regions contributing to minimum and maximum transpiration, and whole-plant and root hydraulic conductance, were identified on chromosomes 1 and 3, while one locus associated with BP transpiration was identified on chromosome 5. CONCLUSIONS This study provides insight into the physiological and genetic control of transpiration in faba bean and opportunities for marker-assisted selection to improve its performance in water-limited environments.
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Affiliation(s)
- Hend Mandour
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
- Genetic Engineering and Biotechnology Research Institute, National Research Centre, Giza, Egypt
| | - Hamid Khazaei
- Natural Resources Institute Finland (LUKE), Latokartanonkaari 9, 00790 Helsinki, Finland
| | - Frederick L Stoddard
- Department of Agricultural Sciences, Viikki Plant Science Centre and Helsinki Institute of Sustainability Science, PO Box 27 (Latokartanonkaari 5-7), FI-00014 University of Helsinki, Helsinki, Finland
| | - Ian C Dodd
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
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8
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Silva GS, Gavassi MA, de Oliveira Carvalho BM, Habermann G. High abscisic acid and low root hydraulic conductivity may explain low leaf hydration in 'Mandarin' lime exposed to aluminum. TREE PHYSIOLOGY 2023; 43:404-417. [PMID: 36349691 DOI: 10.1093/treephys/tpac130] [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: 06/26/2022] [Revised: 10/30/2022] [Accepted: 11/04/2022] [Indexed: 05/03/2023]
Abstract
The first symptom of aluminum (Al) toxicity is the inhibition of root growth, which has been associated with low leaf hydration, with negative consequences for leaf gas exchange including stomatal conductance (gs) observed in many plant species. Here we asked whether low leaf hydration occurs before or after the inhibition of root growth of Citrus × limonia Osbeck ('Mandarin' lime) cultivated for 60 days in nutrient solution with 0 and 1480 μM Al. The length, diameter, surface area and biomass of roots of plants exposed to Al were lower than control plants only at 30 days after treatments (DAT). Until the end of the study, estimated gs (measured by sap flow techniques) was lower than in control plants from 3 DAT, total plant transpiration (Eplant) and root hydraulic conductivity (Lpr) at 7 DAT, and midday leaf water potential (Ψmd) and relative leaf water content at 15 DAT. Abscisic acid (ABA) in leaves was twofold higher in Al-exposed plants 1 DAT, and in roots a twofold higher peak was observed at 15 DAT. As ABA in leaves approached values of control plants after 15 DAT, we propose that low gs of plants exposed to Al is primarily caused by ABA, and the maintenance of low gs could be ascribed to the low Lpr from 7 DAT until the end of the study. Therefore, the low leaf hydration in 'Mandarin' lime exposed to Al does not seem to be caused by root growth inhibition or by a simple consequence of low water uptake due to a stunted root system.
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Affiliation(s)
- Giselle Schwab Silva
- Programa de Pós-Graduação em Biologia Vegetal, Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Av. 24-A, 1515, 13506-900 Rio Claro, SP, Brazil
| | - Marina Alves Gavassi
- Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Av. 24-A, 1515, 13506-900 Rio Claro, SP, Brazil
| | - Brenda Mistral de Oliveira Carvalho
- Programa de Pós-Graduação em Biologia Vegetal, Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Av. 24-A, 1515, 13506-900 Rio Claro, SP, Brazil
| | - Gustavo Habermann
- Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Av. 24-A, 1515, 13506-900 Rio Claro, SP, Brazil
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Huntenburg K, Puértolas J, de Ollas C, Dodd IC. Bi-directional, long-distance hormonal signalling between roots and shoots of soil water availability. PHYSIOLOGIA PLANTARUM 2022; 174:e13697. [PMID: 35526211 PMCID: PMC9320954 DOI: 10.1111/ppl.13697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/22/2022] [Accepted: 05/02/2022] [Indexed: 05/28/2023]
Abstract
While the importance of plant water relations in determining crop response to soil water availability is difficult to over-emphasise, under many circumstances, plants maintain their leaf water status as the soil dries yet shoot gas exchange and growth is restricted. Such observations lead to development of a paradigm that root-to-shoot signals regulate shoot physiology, and a conceptual framework to test the importance of different signals such as plant hormones in these physiological processes. Nevertheless, shoot-to-root (hormonal) signalling also plays an important role in regulating root growth and function and may dominate when larger quantities of a hormone are produced in the shoots than the roots. Here, we review the evidence for acropetal and basipetal transport of three different plant hormones (abscisic acid, jasmonates, strigolactones) that have antitranspirant effects, to indicate the origin and action of these signalling systems. The physiological importance of each transport pathway likely depends on the specific environmental conditions the plant is exposed to, specifically whether the roots or shoots are the first to lose turgor when exposed to drying soil or elevated atmospheric demand, respectively. All three hormones can interact to influence each other's synthesis, degradation and intracellular signalling to augment or attenuate their physiological impacts, highlighting the complexity of unravelling these signalling systems. Nevertheless, such complexity suggests crop improvement opportunities to select for allelic variation in the genes affecting hormonal regulation, and (in selected crops) to augment root-shoot communication by judicious selection of rootstock-scion combinations to ameliorate abiotic stresses.
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Affiliation(s)
- Katharina Huntenburg
- Lancaster Environment CentreLancaster UniversityLancasterUK
- NIAB AgronomyNIABCambridgeUK
| | - Jaime Puértolas
- Lancaster Environment CentreLancaster UniversityLancasterUK
- Department of Botany and Plant Ecology and PhysiologyUniversity of La LagunaSan Cristóbal de La LagunaSpain
| | - Carlos de Ollas
- Departamento de Ciencias Agrarias del Medio NaturalUniversitat Jaume ICastellonSpain
| | - Ian C. Dodd
- Lancaster Environment CentreLancaster UniversityLancasterUK
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Bartlett MK, Sinclair G, Fontanesi G, Knipfer T, Walker MA, McElrone AJ. Root pressure-volume curve traits capture rootstock drought tolerance. ANNALS OF BOTANY 2022; 129:389-402. [PMID: 34668965 PMCID: PMC8944712 DOI: 10.1093/aob/mcab132] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/18/2021] [Indexed: 06/01/2023]
Abstract
BACKGROUND AND AIMS Living root tissues significantly constrain plant water uptake under drought, but we lack functional traits to feasibly screen diverse plants for variation in the drought responses of these tissues. Water stress causes roots to lose volume and turgor, which are crucial to root structure, hydraulics and growth. Thus, we hypothesized that root pressure-volume (p-v) curve traits, which quantify the effects of water potential on bulk root turgor and volume, would capture differences in rootstock drought tolerance. METHODS We used a greenhouse experiment to evaluate relationships between root p-v curve traits and gas exchange, whole-plant hydraulic conductance and biomass under drought for eight grapevine rootstocks that varied widely in drought performance in field trials (101-14, 110R, 420A, 5C, 140-Ru, 1103P, Ramsey and Riparia Gloire), grafted to the same scion variety (Vitis vinifera 'Chardonnay'). KEY RESULTS The traits varied significantly across rootstocks, and droughted vines significantly reduced root turgor loss point (πtlp), osmotic potential at full hydration (πo) and capacitance (C), indicating that roots became less susceptible to turgor loss and volumetric shrinkage. Rootstocks that retained a greater root volume (i.e. a lower C) also maintained more gas exchange under drought. The rootstocks that previous field trials have classified as drought tolerant exhibited significantly lower πtlp, πo and C values in well-watered conditions, but significantly higher πo and πtlp values under water stress, than the varieties classified as drought sensitive. CONCLUSIONS These findings suggest that acclimation in root p-v curve traits improves gas exchange in persistently dry conditions, potentially through impacts on root hydraulics or root to shoot chemical signalling. However, retaining turgor and volume in previously unstressed roots, as these roots deplete wet soil to moderately negative water potentials, could be more important to drought performance in the deep, highly heterogenous rooting zones which grapevines develop under field conditions.
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Affiliation(s)
| | - G Sinclair
- Department of Viticulture & Enology, University of
California, Davis, CA, USA
| | - G Fontanesi
- Department of Viticulture & Enology, University of
California, Davis, CA, USA
| | - T Knipfer
- Department of Viticulture & Enology, University of
California, Davis, CA, USA
- Faculty of Land and Food Systems, The University of British
Columbia, Vancouver, British Columbia, Canada
| | - M A Walker
- Department of Viticulture & Enology, University of
California, Davis, CA, USA
| | - A J McElrone
- Department of Viticulture & Enology, University of
California, Davis, CA, USA
- USDA-ARS, Crops Pathology and Genetics Research Unit,
Davis, CA, USA
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11
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Estimation of China’s Contribution to Global Greening over the Past Three Decades. LAND 2022. [DOI: 10.3390/land11030393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
China’s contribution to global greening is regulated by increasing atmospheric CO2 concentrations, climate change, and land use. Based on TRENDY project data, this study identified that the shifts in China’s contribution to the global leaf area index (LAI) trend strongly reduced during the warming hiatus, translating from 13.42 ± 26.45% during 1982–1998 into 7.91 ± 25.45% during 1999–2012. First, significant negative sensitivities of LAI to enhanced vapor pressure deficit (VPD), when only considering the climate effect derived from TRENDY models in China, were found to have shifted substantially after the late 1990s. However, globally, LAI had positive rather than negative responses to enhanced VPD. These opposing shifts in the response of LAI to enhanced VPD reduced the national contribution to global vegetation greening. Second, shifts in land-use change and their effects on the LAI trends in the two periods in China were accompanied by major changes in land cover and land management intensity, including forestry. Consequently, the contribution of land use in China reduced by −47.68% during the warming hiatus period, as compared with the warming period. Such a shift in the impact of land-use change on LAI simulated by ecosystem models might result from the models’ lack of consideration of conserving and expanding forests with the goal of mitigating climate change for China. Our results highlight the need for ecosystem models to reproduce the enhanced negative impact on global LAI and consider the shifts in man-made adaptation policies (e.g., forest management) to improve terrestrial ecosystem models in the future.
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12
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Leuschner C, Schipka F, Backes K. Stomatal regulation and water potential variation in European beech: challenging the iso/anisohydry concept. TREE PHYSIOLOGY 2022; 42:365-378. [PMID: 34415347 DOI: 10.1093/treephys/tpab104] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
The iso/anisohydric continuum has been used to classify tree species' drought response strategies. The range over which stomata are regulating leaf water potential (ψl) before turgor loss occurs can be described with metrics such as the dependence of ψl on soil water potential (ψsoil) and the size of 'hydroscape area' (HA), but corresponding field data from adult trees are scarce. We examined the stomatal conductance (gs)-ψl relationship in its temporal (diurnal vs seasonal and interannual) and spatial (within-crown vs between-site) variation in European beech, using extensive ψl and gs measurements in the canopy of four beech stands across a precipitation gradient, and complemented the data set by published ψl and gs measurements in further Central European beech stands (including the extreme 2018 drought) in order to cover the full water potential operation space of the species. Both metrics characterize beech as a strictly anisohydric species with δψl/δψsoil >> 1 and HA = 4 MPa2. However, stomates close sensitively in response to increasing vapor pressure deficit, disproving the widely assumed dependence of large ψl variation on looser stomatal control. Characterizing the water status regulation mechanisms of trees requires separating diurnal from day-to-day variation in ψl and gs. The large diurnal and seasonal ψl variation in beech leaves is partly caused by a low leaf tissue elasticity, suggesting that a whole-plant perspective with consideration of osmotic and elastic tissue properties and stem and root hydraulics is needed for fully understanding ψl regulation and the drought tolerance strategy of trees.
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Affiliation(s)
| | - Florian Schipka
- Plant Ecology, University of Goettingen, 37073 Göttingen, Germany
| | - Katharina Backes
- Plant Ecology, University of Goettingen, 37073 Göttingen, Germany
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Williams TB, Dodd IC, Sobeih WY, Paul ND. Ultraviolet radiation causes leaf warming due to partial stomatal closure. HORTICULTURE RESEARCH 2022; 9:uhab066. [PMID: 35043163 PMCID: PMC8944299 DOI: 10.1093/hr/uhab066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 11/12/2021] [Indexed: 06/14/2023]
Abstract
Variation in solar ultraviolet radiation induces a wide-range of plant responses from the cellular to whole-plant scale. We demonstrate here for the first time that partial stomatal closure caused by ultraviolet radiation exposure results in significant increases in leaf temperature. Significant leaf warming in response to ultraviolet radiation was consistent in tomato (Solanum lycopersicum L.) across different experimental approaches. In field experiments where solar ultraviolet radiation was attenuated using filters, exposure to ultraviolet radiation significantly decreased stomatal conductance and increased leaf temperature by up to 1.5°C. Using fluorescent lamps to provide ultraviolet radiation treatments, smaller but significant increases in leaf temperature due to decreases in stomatal conductance occurred in both multi-day controlled environment growth room experiments and short-term (< 2 hours) climate cabinet irradiance response experiments. We show that leaf warming due to partial stomatal closure is independent of any direct warming effects of ultraviolet radiation manipulations. We discuss the implications of ultraviolet radiation-induced warming both for horticultural crop production and understanding broader plant responses to ultraviolet radiation.
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Affiliation(s)
- Tom B Williams
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Ian C Dodd
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Wagdy Y Sobeih
- Arid Agritec Ltd. Gordon Manley Building, Lancaster Environmental Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Nigel D Paul
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
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14
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Zamora O, Schulze S, Azoulay-Shemer T, Parik H, Unt J, Brosché M, Schroeder JI, Yarmolinsky D, Kollist H. Jasmonic acid and salicylic acid play minor roles in stomatal regulation by CO 2 , abscisic acid, darkness, vapor pressure deficit and ozone. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:134-150. [PMID: 34289193 PMCID: PMC8842987 DOI: 10.1111/tpj.15430] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 07/07/2021] [Accepted: 07/14/2021] [Indexed: 05/08/2023]
Abstract
Jasmonic acid (JA) and salicylic acid (SA) regulate stomatal closure, preventing pathogen invasion into plants. However, to what extent abscisic acid (ABA), SA and JA interact, and what the roles of SA and JA are in stomatal responses to environmental cues, remains unclear. Here, by using intact plant gas-exchange measurements in JA and SA single and double mutants, we show that stomatal responsiveness to CO2 , light intensity, ABA, high vapor pressure deficit and ozone either did not or, for some stimuli only, very slightly depended upon JA and SA biosynthesis and signaling mutants, including dde2, sid2, coi1, jai1, myc2 and npr1 alleles. Although the stomata in the mutants studied clearly responded to ABA, CO2 , light and ozone, ABA-triggered stomatal closure in npr1-1 was slightly accelerated compared with the wild type. Stomatal reopening after ozone pulses was quicker in the coi1-16 mutant than in the wild type. In intact Arabidopsis plants, spraying with methyl-JA led to only a modest reduction in stomatal conductance 80 min after treatment, whereas ABA and CO2 induced pronounced stomatal closure within minutes. We could not document a reduction of stomatal conductance after spraying with SA. Coronatine-induced stomatal opening was initiated slowly after 1.5-2.0 h, and reached a maximum by 3 h after spraying intact plants. Our results suggest that ABA, CO2 and light are major regulators of rapid guard cell signaling, whereas JA and SA could play only minor roles in the whole-plant stomatal response to environmental cues in Arabidopsis and Solanum lycopersicum (tomato).
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Affiliation(s)
- Olena Zamora
- Plant Signal Research Group, Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
| | - Sebastian Schulze
- Division of Biological Sciences, Cell and Developmental Biology Section, University of California, San Diego, La Jolla, CA 92093, USA
| | - Tamar Azoulay-Shemer
- Division of Biological Sciences, Cell and Developmental Biology Section, University of California, San Diego, La Jolla, CA 92093, USA
- Fruit Tree Sciences, Agricultural Research Organization (ARO), the Volcani Center, Newe Ya’ar Research Center, Ramat Yishay, Israel, and
| | - Helen Parik
- Plant Signal Research Group, Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
| | - Jaanika Unt
- Plant Signal Research Group, Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
| | - Mikael Brosché
- Plant Signal Research Group, Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, PO Box 65 (Viikinkaari 1), Helsinki FI-00014, Finland
| | - Julian I. Schroeder
- Division of Biological Sciences, Cell and Developmental Biology Section, University of California, San Diego, La Jolla, CA 92093, USA
| | - Dmitry Yarmolinsky
- Plant Signal Research Group, Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
- For correspondence ()
| | - Hannes Kollist
- Plant Signal Research Group, Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
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15
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Jalakas P, Takahashi Y, Waadt R, Schroeder JI, Merilo E. Molecular mechanisms of stomatal closure in response to rising vapour pressure deficit. THE NEW PHYTOLOGIST 2021; 232:468-475. [PMID: 34197630 PMCID: PMC8455429 DOI: 10.1111/nph.17592] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 06/28/2021] [Indexed: 05/26/2023]
Abstract
Vapour pressure deficit (VPD), the difference between the saturation and actual air vapour pressures, indicates the level of atmospheric drought and evaporative pressure on plants. VPD increases during climate change due to changes in air temperature and relative humidity. Rising VPD induces stomatal closure to counteract the VPD-mediated evaporative water loss from plants. There are important gaps in our understanding of the molecular VPD-sensing and signalling mechanisms in stomatal guard cells. Here, we discuss recent advances, research directions and open questions with respect to the three components that participate in VPD-induced stomatal closure in Arabidopsis, including: (1) abscisic acid (ABA)-dependent and (2) ABA-independent regulation of the protein kinase OPEN STOMATA 1 (OST1), and (3) the passive hydraulic stomatal response. In the ABA-dependent component, two models are proposed: ABA may be rapidly synthesised or its basal levels may be involved in the stomatal VPD response. Further studies on stomatal VPD signalling should clarify: (1) whether OST1 activation above basal activity is needed for VPD responses, (2) which components are involved in ABA-independent regulation of OST1, (3) the role of other potential OST1 targets in VPD signalling, and (4) to which extent OST1 contributes to stomatal VPD sensitivity in other plant species.
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Affiliation(s)
- Pirko Jalakas
- Institute of Technology, University of Tartu, 50411 Tartu, Estonia
| | - Yohei Takahashi
- Cell and Developmental Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0116, USA
| | - Rainer Waadt
- Institute of Technology, University of Tartu, 50411 Tartu, Estonia
| | - Julian I. Schroeder
- Cell and Developmental Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0116, USA
| | - Ebe Merilo
- Institute of Technology, University of Tartu, 50411 Tartu, Estonia
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16
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Sabir F, Zarrouk O, Noronha H, Loureiro-Dias MC, Soveral G, Gerós H, Prista C. Grapevine aquaporins: Diversity, cellular functions, and ecophysiological perspectives. Biochimie 2021; 188:61-76. [PMID: 34139292 DOI: 10.1016/j.biochi.2021.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/23/2021] [Accepted: 06/07/2021] [Indexed: 11/30/2022]
Abstract
High-scored premium wines are typically produced under moderate drought stress, suggesting that the water status of grapevine is crucial for wine quality. Aquaporins greatly influence the plant water status by facilitating water diffusion across the plasma membrane in a tightly regulated manner. They adjust the hydraulic conductance of the plasma membrane rapidly and reversibly, which is essential in specific physiological events, including adaptation to soil water scarcity. The comprehension of the sophisticated plant-water relations at the molecular level are thus important to optimize agricultural practices or to assist plant breeding programs. This review explores the recent progresses in understanding the water transport in grapevine at the cellular level through aquaporins and its regulation. Important aspects, including aquaporin structure, diversity, cellular localization, transport properties, and regulation at the cellular and whole plant level are addressed. An ecophysiological perspective about the roles of grapevine aquaporins in plant response to drought stress is also provided.
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Affiliation(s)
- Farzana Sabir
- Linking Landscape, Environment, Agriculture and Food (LEAF), Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017, Lisbon, Portugal; Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003, Lisbon, Portugal.
| | - Olfa Zarrouk
- Association SFCOLAB - Collaborative Laboratory for Digital Innovation in Agriculture, Rua Cândido dos Reis nº1, Espaço SFCOLAB, 2560-312, Torres Vedras, Portugal
| | - Henrique Noronha
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, 4710-057, Braga, Portugal; Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, 5001-801, Vila Real, Portugal
| | - Maria C Loureiro-Dias
- Linking Landscape, Environment, Agriculture and Food (LEAF), Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017, Lisbon, Portugal
| | - Graça Soveral
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003, Lisbon, Portugal
| | - Hernâni Gerós
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, 4710-057, Braga, Portugal; Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, 5001-801, Vila Real, Portugal; Centre of Biological Engineering (CEB), Department of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Catarina Prista
- Linking Landscape, Environment, Agriculture and Food (LEAF), Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017, Lisbon, Portugal; Departamento de Recursos Biologicos, Ambiente e Territorio (DRAT), Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017, Lisbon, Portugal
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17
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Gong L, Liu XD, Zeng YY, Tian XQ, Li YL, Turner NC, Fang XW. Stomatal morphology and physiology explain varied sensitivity to abscisic acid across vascular plant lineages. PLANT PHYSIOLOGY 2021; 186:782-797. [PMID: 33620497 PMCID: PMC8154066 DOI: 10.1093/plphys/kiab090] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/28/2021] [Indexed: 05/10/2023]
Abstract
Abscisic acid (ABA) can induce rapid stomatal closure in seed plants, but the action of this hormone on the stomata of fern and lycophyte species remains equivocal. Here, ABA-induced stomatal closure, signaling components, guard cell K+ and Ca2+ fluxes, vacuolar and actin cytoskeleton dynamics, and the permeability coefficient of guard cell protoplasts (Pf) were analyzed in species spanning the diversity of vascular land plants including 11 seed plants, 6 ferns, and 1 lycophyte. We found that all 11 seed plants exhibited ABA-induced stomatal closure, but the fern and lycophyte species did not. ABA-induced hydrogen peroxide elevation was observed in all species, but the signaling pathway downstream of nitric oxide production, including ion channel activation, was only observed in seed plants. In the angiosperm faba bean (Vicia faba), ABA application caused large vacuolar compartments to disaggregate, actin filaments to disintegrate into short fragments and Pf to increase. None of these changes was observed in the guard cells of the fern Matteuccia struthiopteris and lycophyte Selaginella moellendorffii treated with ABA, but a hypertonic osmotic solution did induce stomatal closure in fern and the lycophyte. Our results suggest that there is a major difference in the regulation of stomata between the fern and lycophyte plants and the seed plants. Importantly, these findings have uncovered the physiological and biophysical mechanisms that may have been responsible for the evolution of a stomatal response to ABA in the earliest seed plants.
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Affiliation(s)
- Lei Gong
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Xu-Dong Liu
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yuan-Yuan Zeng
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Xue-Qian Tian
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yan-Lu Li
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Neil C Turner
- The UWA Institute of Agriculture and UWA School of Agriculture and Environment, The University of Western Australia, M082, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Xiang-Wen Fang
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
- Author for communication: (X.W.F.)
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18
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Geilfus CM, Zhang X, Mithöfer A, Burgel L, Bárdos G, Zörb C. Leaf apoplastic alkalization promotes transcription of the ABA-synthesizing enzyme Vp14 and stomatal closure in Zea mays. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:2686-2695. [PMID: 33345268 PMCID: PMC8006549 DOI: 10.1093/jxb/eraa589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
The chloride component of NaCl salinity causes the leaf apoplast to transiently alkalinize. This transition in pH reduces stomatal aperture. However, whether this apoplastic pH (pHapo) transient initiates stomatal closure by interacting with other chloride stress-induced responses or whether the pH transient alone initiates stomatal closure is unknown. To clarify the problem, the transient alkalinization of the leaf apoplast was mimicked in intact maize (Zea mays L.) by infiltrating near-neutral pH buffers into the leaf apoplast. Effects of the pHapo transient could thus be investigated independently from other chloride stress-derived effects. Microscopy-based ratiometric live pHapo imaging was used to monitor pHapoin planta. LC-MS/MS and real-time quantitative reverse transcription-PCR leaf analyses showed that the artificially induced pHapo transient led to an increase in the concentrations of the stomata-regulating plant hormone abscisic acid (ABA) and in transcripts of the key ABA-synthesizing gene ZmVp14 in the leaf. Since stomatal aperture and stomatal conductance decreased according to pHapo, we conclude that the pHapo transient alone initiates stomatal closure. Therefore, the functionality does not depend on interactions with other compounds induced by chloride stress. Overall, our data indicate that the pH of the leaf apoplast links chloride salinity with the control of stomatal aperture via effects exerted on the transcription of ABA.
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Affiliation(s)
- Christoph-Martin Geilfus
- Division of Controlled Environment Horticulture, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Albrecht-Thaer-Weg, Berlin, Germany
| | - Xudong Zhang
- Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof-West, Stuttgart, Germany
| | - Axel Mithöfer
- Max Planck Institute for Chemical Ecology, Research Group Plant Defense Physiology, Hans-Knöll-Straße, Jena, Germany
| | - Lisa Burgel
- Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof-West, Stuttgart, Germany
| | - Gyöngyi Bárdos
- Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof-West, Stuttgart, Germany
| | - Christian Zörb
- Institute of Crop Science, Quality of Plant Products, University Hohenheim, Schloss, Westhof-West, Stuttgart, Germany
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19
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Westbrook AS, McAdam SAM. Stomatal density and mechanics are critical for high productivity: insights from amphibious ferns. THE NEW PHYTOLOGIST 2021; 229:877-889. [PMID: 32761918 DOI: 10.1111/nph.16850] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
Angiosperm dominance in terrestrial landscapes is partially attributable to high photosynthetic capacities. Angiosperms benefit from diverse anatomical and physiological adaptations, making it difficult to determine which factors may have been prerequisites for the evolution of enhanced photosynthetic rates in this group. We employed a novel approach to this problem: comparisons between angiosperms and Marsileaceae, a family of semi-aquatic ferns that are among the only land plants to match angiosperm photosynthetic rates. We found that Marsileaceae have very high stomatal densities and, like angiosperms but unlike all other ferns previously studied, exhibit wrong-way stomatal responses to excision. These results suggest that stomatal density and a little-studied angiosperm trait, the capacity for lateral displacement of guard cells into neighboring epidermal cells, are crucial for facilitating high rates of gas exchange. Our analysis also associates these adaptations in Marsileaceae with an increased risk of excessive water loss during drought. Our findings indicate that evolution in stomatal physiology was a prerequisite for high photosynthetic capacities in vascular plants and a key driver of the abrupt Cretaceous rise of the angiosperms.
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Affiliation(s)
- Anna S Westbrook
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
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20
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Liang J, Zheng J, Wu Z, Wang H. Strawberry FaNAC2 Enhances Tolerance to Abiotic Stress by Regulating Proline Metabolism. PLANTS (BASEL, SWITZERLAND) 2020; 9:plants9111417. [PMID: 33114021 PMCID: PMC7690739 DOI: 10.3390/plants9111417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/17/2020] [Accepted: 10/21/2020] [Indexed: 05/28/2023]
Abstract
The quality and yields of strawberry plants are seriously affected by abiotic stress every year. NAC (NAM, ATAF, CUC) transcription factors are plant-specific, having various functions in plant development and response to stress. In our study, FaNAC2 from strawberry (Fragaria × ananassa, cultivar "Benihoppe") was isolated and found to be a member of the ATAF sub-family, belonging to the NAC family of transcription factors. FaNAC2 was strongly expressed in the shoot apical meristem and older leaves of strawberries, and was induced by cold, high salinity, and drought stress. To investigate how FaNAC2 functions in plant responses to abiotic stress, transgenic Nicotiana benthamiana plants ectopically overexpressing FaNAC2 were generated. The transgenic plants grew better under salt and cold stress, and, during simulated drought treatment, these transgenic lines not only grew better, but also showed higher seed germination rates than wild-type plants. Gene expression analysis revealed that key genes in proline biosynthesis pathways were up-regulated in FaNAC2 overexpression lines, while its catabolic pathway genes were down-regulated and proline was accumulated more with the overexpression of FaNAC2 after stress treatments. Furthermore, the gene expression of abscisic acid biosynthesis was also promoted. Our results demonstrate that FaNAC2 plays an important positive role in response to different abiotic stresses and may be further utilized to improve the stress tolerance of strawberry plants.
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Affiliation(s)
- Jiahui Liang
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing 100193, China; (J.L.); (J.Z.)
| | - Jing Zheng
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing 100193, China; (J.L.); (J.Z.)
| | - Ze Wu
- Key Laboratory of Landscaping Agriculture, Ministry of Agriculture and Rural Affairs, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China;
| | - Hongqing Wang
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing 100193, China; (J.L.); (J.Z.)
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21
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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.
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22
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Devi MJ, Reddy VR. Stomatal closure response to soil drying at different vapor pressure deficit conditions in maize. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 154:714-722. [PMID: 32758980 DOI: 10.1016/j.plaphy.2020.07.023] [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: 06/09/2020] [Revised: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 06/11/2023]
Abstract
A plant transpiration rate under progressive soil drying remains constant until a threshold fraction of transpirable soil water (FTSW) is reached, and subsequently decreases linearly. The sensitivity of this function and the involvement of abscisic acid (ABA) and aquaporins in such responses have not been compared at various levels of atmospheric evaporative demand conditions. This study was conducted in controlled environment chambers with a drought-tolerant maize hybrid imposing progressive drought stress under three levels of vapor pressure deficit (VPD- 1.2, 2.3, and 3.5 kPa). A shift in threshold-FTSW from 1.2 kPa (FTSW-0.42) VPD to 3.5 kPa(FTSW-0.51) VPD was observed, showing an effect of VPD on stomatal closure response under soil drought conditions. Foliar ABA showed a substantial rise approximately at the same time as of stomatal closure initiated (FTSW-threshold), indicating ABA involvement. As the drought progressed, an increase in plasma membrane intrinsic protein and a decrease in tonoplast intrinsic protein expression levels were observed. Overall, this study suggests the influence of evaporative demand on the initiation of stomatal closure of drought-tolerant maize subjected to soil drying. The sensitivity of stomatal closure was associated with foliar ABA under drought stress but not under high evaporative demand conditions, indicating alternative water conservative mechanisms.
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Affiliation(s)
- Mura Jyostna Devi
- USDA-ARS, Adaptive Cropping Systems Laboratory, Beltsville Agriculture Research Center, Beltsville, MD, United States.
| | - Vangimalla R Reddy
- USDA-ARS, Adaptive Cropping Systems Laboratory, Beltsville Agriculture Research Center, Beltsville, MD, United States
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23
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Cardoso AA, Brodribb TJ, Kane CN, DaMatta FM, McAdam SAM. Osmotic adjustment and hormonal regulation of stomatal responses to vapour pressure deficit in sunflower. AOB PLANTS 2020; 12:plaa025. [PMID: 32665827 PMCID: PMC7346309 DOI: 10.1093/aobpla/plaa025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 06/11/2020] [Indexed: 05/14/2023]
Abstract
Dynamic variation of the stomatal pore in response to changes in leaf-air vapour pressure difference (VPD) constitutes a critical regulation of daytime gas exchange. The stomatal response to VPD has been associated with both foliage abscisic acid (ABA) and leaf water potential (Ψ l ); however, causation remains a matter of debate. Here, we seek to separate hydraulic and hormonal control of stomatal aperture by manipulating the osmotic potential of sunflower leaves. In addition, we test whether stomatal responses to VPD in an ABA-deficient mutant (w-1) of sunflower are similar to the wild type. Stomatal apertures during VPD transitions were closely linked with foliage ABA levels in sunflower plants with contrasting osmotic potentials. In addition, we observed that the inability to synthesize ABA at high VPD in w-1 plants was associated with no dynamic or steady-state stomatal response to VPD. These results for sunflower are consistent with a hormonal, ABA-mediated stomatal responses to VPD rather than a hydraulic-driven stomatal response to VPD.
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Affiliation(s)
- Amanda A Cardoso
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Cade N Kane
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - Fábio M DaMatta
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
- Corresponding author’s e-mail address:
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24
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Frioni T, Tombesi S, Sabbatini P, Squeri C, Lavado Rodas N, Palliotti A, Poni S. Kaolin Reduces ABA Biosynthesis Through the Inhibition of Neoxanthin Synthesis in Grapevines Under Water Deficit. Int J Mol Sci 2020; 21:ijms21144950. [PMID: 32668754 PMCID: PMC7404328 DOI: 10.3390/ijms21144950] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/08/2020] [Accepted: 07/10/2020] [Indexed: 12/24/2022] Open
Abstract
In many viticulture regions, multiple summer stresses are occurring with increased frequency and severity because of warming trends. Kaolin-based particle film technology is a technique that can mitigate the negative effects of intense and/or prolonged drought on grapevine physiology. Although a primary mechanism of action of kaolin is the increase of radiation reflection, some indirect effects are the protection of canopy functionality and faster stress recovery by abscisic acid (ABA) regulation. The physiological mechanism underlying the kaolin regulation of canopy functionality under water deficit is still poorly understood. In a dry-down experiment carried out on grapevines, at the peak of stress and when control vines zeroed whole-canopy net CO2 exchange rates/leaf area (NCER/LA), kaolin-treated vines maintained positive NCER/LA (~2 µmol m-2 s-1) and canopy transpiration (E) (0.57 µmol m-2 s-1). Kaolin-coated leaves had a higher violaxanthin (Vx) + antheraxanthin (Ax) + zeaxanthin (Zx) pool and a significantly lower neoxanthin (Nx) content (VAZ) when water deficit became severe. At the peak of water shortage, leaf ABA suddenly increased by 4-fold in control vines, whereas in kaolin-coated leaves the variation of ABA content was limited. Overall, kaolin prevented the biosynthesis of ABA by avoiding the deviation of the VAZ epoxidation/de-epoxidation cycle into the ABA precursor (i.e., Nx) biosynthetic direction. The preservation of the active VAZ cycle and transpiration led to an improved dissipation of exceeding electrons, explaining the higher resilience of canopy functionality expressed by canopies sprayed by kaolin. These results point out the interaction of kaolin with the regulation of the VAZ cycle and the active mechanism of stomatal conductance regulation.
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Affiliation(s)
- Tommaso Frioni
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; (T.F.); (C.S.); (S.P.)
| | - Sergio Tombesi
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; (T.F.); (C.S.); (S.P.)
- Correspondence: ; Tel.: +390523599221
| | - Paolo Sabbatini
- Department of Horticulture, Michigan State University, 1066 Bogue Street, East Lansing, MI 48824, USA;
| | - Cecilia Squeri
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; (T.F.); (C.S.); (S.P.)
| | - Nieves Lavado Rodas
- CICYTEX (Junta de Extremadura), Finca La Orden, Ctra. A-V, km 372, Guadajira, 06187 Badajoz, Spain;
| | - Alberto Palliotti
- Department of Agricultural, Food and Environmental Sciences, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy;
| | - Stefano Poni
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; (T.F.); (C.S.); (S.P.)
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McCauley CL, McAdam SAM, Bhide K, Thimmapuram J, Banks JA, Young BG. Transcriptomics in Erigeron canadensis reveals rapid photosynthetic and hormonal responses to auxin herbicide application. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:3701-3709. [PMID: 32161961 PMCID: PMC7307852 DOI: 10.1093/jxb/eraa124] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/10/2020] [Indexed: 05/14/2023]
Abstract
The perception pathway for endogenous auxin has been well described, yet the mode of action of synthetic auxin herbicides, used for >70 years, remains uncharacterized. We utilized transcriptomics and targeted physiological studies to investigate the unknown rapid response to synthetic auxin herbicides in the globally problematic weed species Erigeron canadensis. Synthetic auxin herbicide application consistently and rapidly down-regulated the photosynthetic machinery. At the same time, there was considerable perturbation to the expression of many genes related to phytohormone metabolism and perception. In particular, auxin herbicide application enhanced the expression of the key abscisic acid biosynthetic gene, 9-cis-epoxycarotenoid deoxygenase (NCED). The increase in NCED expression following auxin herbicide application led to a rapid biosynthesis of abscisic acid (ABA). This increase in ABA levels was independent of a loss of cell turgor or an increase in ethylene levels, both proposed triggers for rapid ABA biosynthesis. The levels of ABA in the leaf after auxin herbicide application continued to increase as plants approached death, up to >3-fold higher than in the leaves of plants that were drought stressed. We propose a new model in which synthetic auxin herbicides trigger plant death by the whole-scale, rapid, down-regulation of photosynthetic processes and an increase in ABA levels through up-regulation of NCED expression, independent of ethylene levels or a loss of cell turgor.
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Affiliation(s)
- Cara L McCauley
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
- Correspondence:
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - Ketaki Bhide
- Bioinformatics Core, Purdue University, West Lafayette, IN, USA
| | | | - Jo Ann Banks
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - Bryan G Young
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
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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.
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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
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Lanning M, Wang L, Novick KA. The importance of cuticular permeance in assessing plant water-use strategies. TREE PHYSIOLOGY 2020; 40:425-432. [PMID: 32091105 DOI: 10.1093/treephys/tpaa020] [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: 10/22/2019] [Revised: 01/20/2020] [Accepted: 02/22/2020] [Indexed: 06/10/2023]
Abstract
Accurate understanding of plant responses to water stress is increasingly important for quantification of ecosystem carbon and water cycling under future climates. Plant water-use strategies can be characterized across a spectrum of water stress responses, from tight stomatal control (isohydric) to distinctly less stomatal control (anisohydric). A recent and popular classification method of plant water-use strategies utilizes the regression slope of predawn and midday leaf water potentials, σ, to reflect the coupling of soil water availability (predawn leaf water potential) and stomatal dynamics (daily decline in leaf water potential). This type of classification is important in predicting ecosystem drought response and resiliency. However, it fails to explain the relative stomatal responses to drought of Acer sacharrum and Quercus alba, improperly ranking them on the spectrum of isohydricity. We argue this inconsistency may be in part due to the cuticular conductance of different species. We used empirical and modeling evidence to show that plants with more permeable cuticles are more often classified as anisohydric; the σ values of those species were very well correlated with measured cuticular permeance. Furthermore, we found that midday leaf water potential in species with more permeable cuticles would continue to decrease as soils become drier, but not in those with less permeable cuticles. We devised a diagnostic parameter, Γ, to identify circumstances where the impact of cuticular conductance could cause species misclassification. The results suggest that cuticular conductance needs to be considered to better understand plant water-use strategies and to accurately predict forest responses to water stress under future climate scenarios.
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Affiliation(s)
- Matthew Lanning
- Department of Earth Science, Indiana University - Purdue University Indianapolis, 723 West Michigan Street, Indianapolis, IN 46202, USA
| | - Lixin Wang
- Department of Earth Science, Indiana University - Purdue University Indianapolis, 723 West Michigan Street, Indianapolis, IN 46202, USA
| | - Kimberly A Novick
- School of Public and Environmental Affairs, Indiana University Bloomington, 1315 East Tenth Street, Bloomington, IN 47405, USA
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Kaiser E, Morales A, Harbinson J, Heuvelink E, Marcelis LFM. High Stomatal Conductance in the Tomato Flacca Mutant Allows for Faster Photosynthetic Induction. FRONTIERS IN PLANT SCIENCE 2020; 11:1317. [PMID: 32983206 PMCID: PMC7477092 DOI: 10.3389/fpls.2020.01317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 08/11/2020] [Indexed: 05/05/2023]
Abstract
Due to their slow movement and closure upon shade, partially closed stomata can be a substantial limitation to photosynthesis in variable light intensities. The abscisic acid deficient flacca mutant in tomato (Solanum lycopersicum) displays very high stomatal conductance (gs ). We aimed to determine to what extent this substantially increased gs affects the rate of photosynthetic induction. Steady-state and dynamic photosynthesis characteristics were measured in flacca and wildtype leaves, by the use of simultaneous gas exchange and chlorophyll fluorometry. The steady-state response of photosynthesis to CO2, maximum quantum efficiency of photosystem II photochemistry (Fv/Fm ), as well as mesophyll conductance to CO2 diffusion were not significantly different between genotypes, suggesting similar photosynthetic biochemistry, photoprotective capacity, and internal CO2 permeability. When leaves adapted to shade (50 µmol m-2 s-1) at 400 µbar CO2 partial pressure and high humidity (7 mbar leaf-to-air vapour pressure deficit, VPD) were exposed to high irradiance (1500 µmol m-2 s-1), photosynthetic induction was faster in flacca compared to wildtype leaves, and this was attributable to high initial gs in flacca (~0.6 mol m-2 s-1): in flacca, the times to reach 50 (t50 ) and 90% (t90 ) of full photosynthetic induction were 91 and 46% of wildtype values, respectively. Low humidity (15 mbar VPD) reduced gs and slowed down photosynthetic induction in the wildtype, while no change was observed in flacca; under low humidity, t50 was 63% and t90 was 36% of wildtype levels in flacca. Photosynthetic induction in low CO2 partial pressure (200 µbar) increased gs in the wildtype (but not in flacca), and revealed no differences in the rate of photosynthetic induction between genotypes. Effects of higher gs in flacca were also visible in transients of photosystem II operating efficiency and non-photochemical quenching. Our results show that at ambient CO2 partial pressure, wildtype gs is a substantial limitation to the rate of photosynthetic induction, which flacca overcomes by keeping its stomata open at all times, and it does so at the cost of reduced water use efficiency.
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Affiliation(s)
- Elias Kaiser
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, Wageningen, Netherlands
- *Correspondence: Elias Kaiser,
| | - Alejandro Morales
- Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, Wageningen, Netherlands
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht University, Utrecht, Netherlands
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Utrecht, Netherlands
| | - Jeremy Harbinson
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, Wageningen, Netherlands
| | - Ep Heuvelink
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, Wageningen, Netherlands
| | - Leo F. M. Marcelis
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, Wageningen, Netherlands
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Brunetti C, Gori A, Marino G, Latini P, Sobolev AP, Nardini A, Haworth M, Giovannelli A, Capitani D, Loreto F, Taylor G, Mugnozza GS, Harfouche A, Centritto M. Dynamic changes in ABA content in water-stressed Populus nigra: effects on carbon fixation and soluble carbohydrates. ANNALS OF BOTANY 2019; 124:627-644. [PMID: 30715123 PMCID: PMC6821382 DOI: 10.1093/aob/mcz005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 01/03/2019] [Indexed: 05/20/2023]
Abstract
BACKGROUND AND AIMS Hydraulic and chemical signals operate in tandem to regulate systemic plant responses to drought. Transport of abscisic acid (ABA) through the xylem and phloem from the root to shoot has been suggested to serve as the main signal of water deficit. There is evidence that ABA and its ABA-glycosyl-ester (ABA-GE) are also formed in leaves and stems through the chloroplastic 2-C-methylerythritol-5-phosphate (MEP) pathway. This study aimed to evaluate how hormonal and hydraulic signals contribute to optimize stomatal (gs), mesophyll (gm) and leaf hydraulic (Kleaf) conductance under well-watered and water-stressed conditions in Populus nigra (black poplar) plants. In addition, we assessed possible relationships between ABA and soluble carbohydrates within the leaf and stem. METHODS Plants were subjected to three water treatments: well-watered (WW), moderate stress (WS1) and severe stress (WS2). This experimental set-up enabled a time-course analysis of the response to water deficit at the physiological [leaf gas exchange, plant water relations, (Kleaf)], biochemical (ABA and its metabolite/catabolite quantification in xylem sap, leaves, wood, bark and roots) and molecular (gene expression of ABA biosynthesis) levels. KEY RESULTS Our results showed strong coordination between gs, gm and Kleaf under water stress, which reduced transpiration and increased intrinsic water use efficiency (WUEint). Analysis of gene expression of 9-cis-epoxycarotenoid dioxygenase (NCED) and ABA content in different tissues showed a general up-regulation of the biosynthesis of this hormone and its finely-tuned catabolism in response to water stress. Significant linear relationships were found between soluble carbohydrates and ABA contents in both leaves and stems, suggesting a putative function for this hormone in carbohydrate mobilization under severe water stress. CONCLUSIONS This study demonstrates the tight regulation of the photosynthetic machinery by levels of ABA in different plants organs on a daily basis in both well-watered and water stress conditions to optimize WUEint and coordinate whole plant acclimation responses to drought.
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Affiliation(s)
- Cecilia Brunetti
- Trees and Timber Institute, National Research Council of Italy, Sesto Fiorentino (FI), Italy
| | - Antonella Gori
- University of Florence, Department of Agri-Food Production and Environmental Sciences, Florence, Italy
| | - Giovanni Marino
- Trees and Timber Institute, National Research Council of Italy, Sesto Fiorentino (FI), Italy
| | - Paolo Latini
- Dipartimento per la Innovazione nei sistemi Biologici, Agroalimentari e Forestali (DIBAF), Università degli Studi della Tuscia, Viterbo, Italy
| | - Anatoly P Sobolev
- Istituto di Metodologie Chimiche, Consiglio Nazionale delle Ricerche, Monterotondo (Roma), Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy
| | - Matthew Haworth
- Trees and Timber Institute, National Research Council of Italy, Sesto Fiorentino (FI), Italy
| | - Alessio Giovannelli
- Trees and Timber Institute, National Research Council of Italy, Sesto Fiorentino (FI), Italy
| | - Donatella Capitani
- Istituto di Metodologie Chimiche, Consiglio Nazionale delle Ricerche, Monterotondo (Roma), Italy
| | - Francesco Loreto
- Dipartimento di Scienze Bio-Agroalimentari, Consiglio Nazionale delle Ricerche, Roma, Italy
| | - Gail Taylor
- Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Highfield Campus, Southampton, UK
- Department of Plant Sciences, University of California-Davis, CA, USA
| | - Giuseppe Scarascia Mugnozza
- Dipartimento per la Innovazione nei sistemi Biologici, Agroalimentari e Forestali (DIBAF), Università degli Studi della Tuscia, Viterbo, Italy
| | - Antoine Harfouche
- Dipartimento per la Innovazione nei sistemi Biologici, Agroalimentari e Forestali (DIBAF), Università degli Studi della Tuscia, Viterbo, Italy
| | - Mauro Centritto
- Trees and Timber Institute, National Research Council of Italy, Sesto Fiorentino (FI), Italy
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30
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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: 176] [Impact Index Per Article: 35.2] [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.
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Affiliation(s)
- Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
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31
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Huber AE, Melcher PJ, Piñeros MA, Setter TL, Bauerle TL. Signal coordination before, during and after stomatal closure in response to drought stress. THE NEW PHYTOLOGIST 2019; 224:675-688. [PMID: 31364171 DOI: 10.1111/nph.16082] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/22/2019] [Indexed: 05/27/2023]
Abstract
Signal coordination in response to changes in water availability remains unclear, as does the role of embolism events in signaling drought stress. Sunflowers were exposed to two drought treatments of varying intensity while simultaneously monitoring changes in stomatal conductance, acoustic emissions (AE), turgor pressure, surface-level electrical potential, organ-level water potential and leaf abscisic acid (ABA) concentration. Leaf, stem and root xylem vulnerability to embolism were measured with the single vessel injection technique. In both drought treatments, it was found that AE events and turgor changes preceded the onset of stomatal closure, whereas electrical surface potentials shifted concurrently with stomatal closure. Leaf-level ABA concentration did not change until after stomata were closed. Roots and petioles were equally vulnerable to drought stress based on the single vessel injection technique. However, anatomical analysis of the xylem indicated that the increased AE events were not a result of xylem embolism formation. Additionally, roots and stems never reached a xylem pressure threshold that would initiate runaway embolism throughout the entire experiment. It is concluded that stomatal closure was not embolism-driven, but, rather, that onset of stomatal closure was most closely correlated with the hydraulic signal from changes in leaf turgor.
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Affiliation(s)
- Annika E Huber
- School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, NY, USA
| | - Peter J Melcher
- Biology Department, Center for Natural Sciences, Ithaca College, Ithaca, NY, 14850, NY, USA
| | - Miguel A Piñeros
- School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, NY, USA
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, 14853, NY, USA
| | - Tim L Setter
- School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, NY, USA
| | - Taryn L Bauerle
- School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, NY, USA
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Yonemura S, Kodama N, Taniguchi Y, Ikawa H, Adachi S, Hanba YT. A high-performance system of multiple gas-exchange chambers with a laser spectrometer to estimate leaf photosynthesis, stomatal conductance, and mesophyll conductance. JOURNAL OF PLANT RESEARCH 2019; 132:705-718. [PMID: 31363942 DOI: 10.1007/s10265-019-01127-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Direct measurements of ecophysiological processes such as leaf photosynthesis are often hampered due to the excessive time required for gas-exchange measurements and the limited availability of multiple gas analyzers. Although recent advancements in commercially available instruments have improved the ability to take measurements more conveniently, the amount of time required for each plant sample to acclimate to chamber conditions has not been sufficiently reduced. Here we describe a system of multiple gas-exchange chambers coupled with a laser spectrometer that employs tunable diode laser absorption spectroscopy (TDLAS) to measure leaf photosynthesis, stomatal conductance, and mesophyll conductance. Using four gas-exchange chambers minimizes the time loss associated with acclimation for each leaf sample. System operation is semiautomatic, and leaf temperature, humidity, and CO2 concentration can be regulated and monitored remotely by a computer system. The preliminary results with rice leaf samples demonstrated that the system is capable of high-throughput measurements, which is necessary to obtain better representativeness of the ecophysiological characteristics of plant samples.
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Affiliation(s)
- Seiichiro Yonemura
- Institute for Agro-Environmental Sciences, NARO, 3-1-3 Kannondai, Tsukuba, 305-8604, Japan.
| | - Naomi Kodama
- Institute for Agro-Environmental Sciences, NARO, 3-1-3 Kannondai, Tsukuba, 305-8604, Japan
- School of Human Science and Environment, Hyogo University, 1-1-12 Shinzaike-honcho, Himeji, 607-0092, Japan
| | - Yojiro Taniguchi
- Institute of Crop Science, NARO, 2-1-18 Kannondai, Tsukuba, 305-8602, Japan
| | - Hiroki Ikawa
- Institute for Agro-Environmental Sciences, NARO, 3-1-3 Kannondai, Tsukuba, 305-8604, Japan
| | - Shunsuke Adachi
- Institute of Crop Science, NARO, 2-1-18 Kannondai, Tsukuba, 305-8602, Japan
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo, 183-8509, Japan
| | - Yuko T Hanba
- Faculty of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
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Morris RJ, Blyth M. How water flow, geometry, and material properties drive plant movements. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3549-3560. [PMID: 31112593 DOI: 10.1093/jxb/erz167] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 04/08/2019] [Indexed: 06/09/2023]
Abstract
Plants are dynamic. They adjust their shape for feeding, defence, and reproduction. Such plant movements are critical for their survival. We present selected examples covering a range of movements from single cell to tissue level and over a range of time scales. We focus on reversible turgor-driven shape changes. Recent insights into the mechanisms of stomata, bladderwort, the waterwheel, and the Venus flytrap are presented. The underlying physical principles (turgor, osmosis, membrane permeability, wall stress, snap buckling, and elastic instability) are highlighted, and advances in our understanding of these processes are summarized.
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Affiliation(s)
- Richard J Morris
- Computational and Systems Biology, John Innes Centre, Norwich, UK
| | - Mark Blyth
- School of Mathematics, University of East Anglia, Norwich, UK
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Gimenez BO, Jardine KJ, Higuchi N, Negrón-Juárez RI, Sampaio-Filho IDJ, Cobello LO, Fontes CG, Dawson TE, Varadharajan C, Christianson DS, Spanner GC, Araújo AC, Warren JM, Newman BD, Holm JA, Koven CD, McDowell NG, Chambers JQ. Species-Specific Shifts in Diurnal Sap Velocity Dynamics and Hysteretic Behavior of Ecophysiological Variables During the 2015-2016 El Niño Event in the Amazon Forest. FRONTIERS IN PLANT SCIENCE 2019; 10:830. [PMID: 31316536 PMCID: PMC6611341 DOI: 10.3389/fpls.2019.00830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 06/07/2019] [Indexed: 05/11/2023]
Abstract
Current climate change scenarios indicate warmer temperatures and the potential for more extreme droughts in the tropics, such that a mechanistic understanding of the water cycle from individual trees to landscapes is needed to adequately predict future changes in forest structure and function. In this study, we contrasted physiological responses of tropical trees during a normal dry season with the extreme dry season due to the 2015-2016 El Niño-Southern Oscillation (ENSO) event. We quantified high resolution temporal dynamics of sap velocity (Vs), stomatal conductance (gs) and leaf water potential (ΨL) of multiple canopy trees, and their correlations with leaf temperature (Tleaf) and environmental conditions [direct solar radiation, air temperature (Tair) and vapor pressure deficit (VPD)]. The experiment leveraged canopy access towers to measure adjacent trees at the ZF2 and Tapajós tropical forest research (near the cities of Manaus and Santarém). The temporal difference between the peak of gs (late morning) and the peak of VPD (early afternoon) is one of the major regulators of sap velocity hysteresis patterns. Sap velocity displayed species-specific diurnal hysteresis patterns reflected by changes in Tleaf. In the morning, Tleaf and sap velocity displayed a sigmoidal relationship. In the afternoon, stomatal conductance declined as Tleaf approached a daily peak, allowing ΨL to begin recovery, while sap velocity declined with an exponential relationship with Tleaf. In Manaus, hysteresis indices of the variables Tleaf-Tair and ΨL-Tleaf were calculated for different species and a significant difference (p < 0.01, α = 0.05) was observed when the 2015 dry season (ENSO period) was compared with the 2017 dry season ("control scenario"). In some days during the 2015 ENSO event, Tleaf approached 40°C for all studied species and the differences between Tleaf and Tair reached as high at 8°C (average difference: 1.65 ± 1.07°C). Generally, Tleaf was higher than Tair during the middle morning to early afternoon, and lower than Tair during the early morning, late afternoon and night. Our results support the hypothesis that partial stomatal closure allows for a recovery in ΨL during the afternoon period giving an observed counterclockwise hysteresis pattern between ΨL and Tleaf.
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Affiliation(s)
| | - Kolby J. Jardine
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Niro Higuchi
- National Institute of Amazonian Research (INPA), Manaus, Brazil
| | - Robinson I. Negrón-Juárez
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | | | | | - Clarissa G. Fontes
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Todd E. Dawson
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Charuleka Varadharajan
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Danielle S. Christianson
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | | | | | - Jeffrey M. Warren
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Brent D. Newman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Jennifer A. Holm
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Charles D. Koven
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Nate G. McDowell
- Pacific Northwest National Laboratory, Richland, WA, United States
| | - Jeffrey Q. Chambers
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Geography, University of California, Berkeley, Berkeley, CA, United States
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Jiao XC, Song XM, Zhang DL, Du QJ, Li JM. Coordination between vapor pressure deficit and CO 2 on the regulation of photosynthesis and productivity in greenhouse tomato production. Sci Rep 2019; 9:8700. [PMID: 31213627 PMCID: PMC6581957 DOI: 10.1038/s41598-019-45232-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 06/01/2019] [Indexed: 11/10/2022] Open
Abstract
The high vapor pressure deficit (VPD) in some arid and semi-arid climates creates undesirable conditions for the growth of tomato plants (Solanum lycopersicum L., cv. Jinpeng). The global CO2 concentration ([CO2]) has also risen in recent years to levels above 400 μmol·mol-1. However, the coordinated effect of VPD and [CO2] on tomato plant growth remains unclear, especially at VPDs of 5-6 kPa or even higher that are extremely detrimental to plant growth. Here, we explore the interaction of VPD and [CO2] on plant water status, stomatal characteristics, and gas exchange parameters in summer greenhouses in a semi-arid area. Plants were grown in four adjacent glass greenhouses with different environmental conditions: (i) high VPD + low [CO2] representing natural/control conditions; (ii) high VPD + high [CO2] representing enriched CO2; (iii) low VPD + low [CO2] representing reduced VPD; and (iv) low VPD + high [CO2] representing reduced VPD and enriched CO2. Reducing the VPD alleviated the water stress of the plant and increased the gas exchange area of the leaf, which was beneficial to the entry of CO2 into the leaf. At this time, the increase of [CO2] was more beneficial to promote the photosynthetic rate and then improve the water use efficiency and yield.
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Affiliation(s)
- Xiao-Cong Jiao
- College of Horticulture, Northwest Agriculture & Forest University, Yangling, 712100, Shaanxi, China
| | - Xiao-Ming Song
- College of Horticulture, Northwest Agriculture & Forest University, Yangling, 712100, Shaanxi, China
| | - Da-Long Zhang
- College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, 271018, Shandong, China
| | - Qing-Jie Du
- College of Horticulture, Northwest Agriculture & Forest University, Yangling, 712100, Shaanxi, China
| | - Jian-Ming Li
- College of Horticulture, Northwest Agriculture & Forest University, Yangling, 712100, Shaanxi, China.
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Batool A, Akram NA, Cheng ZG, Lv GC, Ashraf M, Afzal M, Xiong JL, Wang JY, Xiong YC. Physiological and biochemical responses of two spring wheat genotypes to non-hydraulic root-to-shoot signalling of partial and full root-zone drought stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 139:11-20. [PMID: 30875531 DOI: 10.1016/j.plaphy.2019.03.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 02/27/2019] [Accepted: 03/04/2019] [Indexed: 05/07/2023]
Abstract
Non-hydraulic root-sourced signal (nHRS) is so far affirmed to be a unique positive early-warning response to drying soil, however its physiological and agronomic implications are still unclear. We designed two contrast methods to induce nHRS in two wheat (Triticum aestivum L.) genotypes released in different decades under pot-culture conditions. Partial root-zone stress (PS) was performed using the method of split-root alternative water supply (one half wetting and the other drying) to induce the continuous operation of nHRS, and full root-zone stress (FS) was subjected to whole root system to periodic operation of nHRS. nHRS-mediated signalling increased abscisic acid (ABA) production and triggered ROS (reactive oxygen species) generation, which, thereby, led to up-regulation of antioxidant defense system. Cytokinin synthesis reduced during drought stress while proline and malodialdehyde (MDA) content were increased. Regardless of drought treatment methods and wheat genotype, a significant decrease in grain yield, root biomass and above-ground biomass (p < 0.05) was observed, without significant changes in root-to-shoot ratio. Harvest index was increased, proposing that more energy was allocated to reproductive organs during the action of nHRS. Moreover, higher water use efficiency was witnessed in PS. The data suggest that nHRS triggered ABA accumulation, thereby closing stomata, and reducing water use and also decreases the production of ROS and improves the antioxidant defence enzymes, thus enhancing drought tolerance. This survey of different-decade genotypes suggests that advances in grain yield and drought tolerance would be made by targeted selection for a wheat genetic resource.
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Affiliation(s)
- Asfa Batool
- State Key Laboratory of Grassland Agro-Ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | | | - Zheng-Guo Cheng
- State Key Laboratory of Grassland Agro-Ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Guang-Chao Lv
- State Key Laboratory of Grassland Agro-Ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Muhammad Ashraf
- State Key Laboratory of Grassland Agro-Ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China; Faculty of Agriculture, The University of Sargodha, Sargodha, 40100, Pakistan
| | - Muhammad Afzal
- Faculty of Agriculture, The University of Sargodha, Sargodha, 40100, Pakistan
| | - Jun-Lan Xiong
- State Key Laboratory of Grassland Agro-Ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Jian-Yong Wang
- State Key Laboratory of Grassland Agro-Ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - You-Cai Xiong
- State Key Laboratory of Grassland Agro-Ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
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Sussmilch FC, Schultz J, Hedrich R, Roelfsema MRG. Acquiring Control: The Evolution of Stomatal Signalling Pathways. TRENDS IN PLANT SCIENCE 2019; 24:342-351. [PMID: 30797685 DOI: 10.1016/j.tplants.2019.01.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/02/2019] [Accepted: 01/10/2019] [Indexed: 05/24/2023]
Abstract
In vascular plants, stomata balance two opposing functions: they open to facilitate CO2 uptake and close to prevent excessive water loss. Here, we discuss the evolution of three major signalling pathways that are known to control stomatal movements in angiosperms in response to light, CO2, and abscisic acid (ABA). We examine the evolutionary origins of key signalling genes involved in these pathways, and compare their expression patterns between an angiosperm and moss. We propose that variation in stomatal sensitivity to stimuli between plant groups are rooted in differences in: (i) gene presence/absence, (ii) specificity of gene spatial expression pattern, and (iii) protein characteristics and functional interactions.
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Affiliation(s)
- Frances C Sussmilch
- Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, D-97082 Würzburg, Germany
| | - Jörg Schultz
- Center for Computational and Theoretical Biology, University of Würzburg, D-97218 Würzburg, Germany
| | - Rainer Hedrich
- Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, D-97082 Würzburg, Germany
| | - M Rob G Roelfsema
- Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, D-97082 Würzburg, Germany.
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Bertolino LT, Caine RS, Gray JE. Impact of Stomatal Density and Morphology on Water-Use Efficiency in a Changing World. FRONTIERS IN PLANT SCIENCE 2019; 10:225. [PMID: 30894867 PMCID: PMC6414756 DOI: 10.3389/fpls.2019.00225] [Citation(s) in RCA: 196] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/11/2019] [Indexed: 05/18/2023]
Abstract
Global warming and associated precipitation changes will negatively impact on many agricultural ecosystems. Major food production areas are expected to experience reduced water availability and increased frequency of drought over the coming decades. In affected areas, this is expected to reduce the production of important food crops including wheat, rice, and maize. The development of crop varieties able to sustain or improve yields with less water input is, therefore, a priority for crop research. Almost all water used for plant growth is lost to the atmosphere by transpiration through stomatal pores on the leaf epidermis. By altering stomatal pore apertures, plants are able to optimize their CO2 uptake for photosynthesis while minimizing water loss. Over longer periods, stomatal development may also be adjusted, with stomatal size and density being adapted to suit the prevailing conditions. Several approaches to improve drought tolerance and water-use efficiency through the modification of stomatal traits have been tested in the model plant Arabidopsis thaliana. However, there is surprisingly little known about the stomata of crop species. Here, we review the current understanding of how stomatal number and morphology are involved in regulating water-use efficiency. Moreover, we discuss the potential and limitations of manipulating stomatal development to increase drought tolerance and to reduce water loss in crops as the climate changes.
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Affiliation(s)
- Lígia T. Bertolino
- Grantham Centre for Sustainable Futures, University of Sheffield, Sheffield, United Kingdom
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Robert S. Caine
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Julie E. Gray
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
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Jauregui I, Rothwell SA, Taylor SH, Parry MAJ, Carmo-Silva E, Dodd IC. Whole plant chamber to examine sensitivity of cereal gas exchange to changes in evaporative demand. PLANT METHODS 2018; 14:97. [PMID: 30410567 PMCID: PMC6211548 DOI: 10.1186/s13007-018-0357-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 10/08/2018] [Indexed: 05/29/2023]
Abstract
BACKGROUND Improving plant water use efficiency (WUE) is a major target for improving crop yield resilience to adverse climate change. Identifying genetic variation in WUE usually relies on instantaneous measurements of photosynthesis (An) and transpiration (Tr), or integrative measurements of carbon isotope discrimination, at the leaf level. However, leaf gas exchange measurements alone do not adequately represent whole plant responses, especially if evaporative demand around the plant changes. RESULTS Here we describe a whole plant gas exchange system that can rapidly alter evaporative demand when measuring An, Tr and intrinsic WUE (iWUE) and identify genetic variation in this response. An was not limited by VPD under steady-state conditions but some wheat cultivars restricted Tr under high evaporative demand, thereby improving iWUE. These changes may be ABA-dependent, since the barley ABA-deficient mutant (Az34) failed to restrict Tr under high evaporative demand. Despite higher Tr, Az34 showed lower An than wild-type (WT) barley because of limitations in Rubisco carboxylation activity. Tr and An of Az34 were more sensitive than WT barley to exogenous spraying with ABA, which restricted photosynthesis via substrate limitation and decreasing Rubisco activation. CONCLUSIONS Examining whole plant gas exchange responses to altered VPD can identify genetic variation in whole plant iWUE, and facilitate an understanding of the underlying mechanism(s).
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Affiliation(s)
- Iván Jauregui
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ UK
- Present Address: Plant Genetics, TERRA Teaching and Research Center, Gembloux Agro Bio-Tech, University of Liège, Gembloux, 5030 Belgium
| | - Shane A. Rothwell
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ UK
| | - Samuel H. Taylor
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ UK
| | - Martin A. J. Parry
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ UK
| | | | - Ian C. Dodd
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ UK
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Devi MJ, Reddy VR. Transpiration Response of Cotton to Vapor Pressure Deficit and Its Relationship With Stomatal Traits. FRONTIERS IN PLANT SCIENCE 2018; 9:1572. [PMID: 30420866 PMCID: PMC6218332 DOI: 10.3389/fpls.2018.01572] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/09/2018] [Indexed: 05/11/2023]
Abstract
Many studies have demonstrated that the cotton in warm environments is vulnerable to water-limitations thus reducing the yield. A number of plant traits have been recommended to ameliorate the effects of water deficits on plant growth and yield. Limitation on maximum transpiration rate (TR) under high vapor pressure deficit (VPD), usually occurs during midday, is often considered as a water conservation trait. The genotypes with this trait are desirable in high VPD environments where water deficits commonly develop in the later part of the growing season. Our objective of the study was to find the genotypic variation for the trait limited TR under high VPD and also to study leaf temperature, water potential, photosynthesis, and stomatal conductance responses. Also, our objective was also to study the structural changes in the stomatal traits when exposed to long term high VPD conditions and involvement in such responses. In the present study, 17 cotton genotypes were studied for their (TR) response to various VPD environments under well irrigated conditions. Out of 17, eight genotypes limited TR after approximately 2 kPa VPD and rest of them increased their TR with increased VPD. Five selected genotypes with different TR response to increasing VPD were further studied for gas exchange and stomatal properties. All genotypes, irrespective of exhibiting limited TR at high VPD, reduced stomatal conductance, photosynthesis and water potential at high VPD of 3.3 kPa. The genotypes with limited TR modified their stomatal traits mostly on the adaxial surface with frequent and small stomata under high VPD. The genotypes with limited TR also exhibited an increase in epidermal cell expansion and stomatal index at contrasting VPD gradients to effectively balance the liquid and vapor phase conductance to limit TR at high VPD.
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Affiliation(s)
- Mura Jyostna Devi
- Adaptive Cropping Systems Laboratory, Beltsville Agricultural Research Center, United States Department of Agriculture-Agricultural Research Service-Northeast Area, Beltsville, MD, United States
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - Vangimalla R. Reddy
- Adaptive Cropping Systems Laboratory, Beltsville Agricultural Research Center, United States Department of Agriculture-Agricultural Research Service-Northeast Area, Beltsville, MD, United States
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Flexas J, Carriquí M, Nadal M. Gas exchange and hydraulics during drought in crops: who drives whom? JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3791-3795. [PMID: 30032258 PMCID: PMC6054177 DOI: 10.1093/jxb/ery235] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Affiliation(s)
- Jaume Flexas
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears-Instituto de Agroecología y Economía del Agua (INAGEA), Palma, Illes Balears, Spain
| | - Marc Carriquí
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears-Instituto de Agroecología y Economía del Agua (INAGEA), Palma, Illes Balears, Spain
| | - Miquel Nadal
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears-Instituto de Agroecología y Economía del Agua (INAGEA), Palma, Illes Balears, Spain
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Wang X, Du T, Huang J, Peng S, Xiong D. Leaf hydraulic vulnerability triggers the decline in stomatal and mesophyll conductance during drought in rice. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:4033-4045. [PMID: 29788146 PMCID: PMC6054168 DOI: 10.1093/jxb/ery188] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/14/2018] [Indexed: 05/21/2023]
Abstract
Understanding the physiological responses of crops to drought is important for ensuring sustained crop productivity under climate change, which is expected to exacerbate the frequency and intensity of periods of drought. Drought responses involve multiple traits, and the correlations between these traits are poorly understood. Using a variety of techniques, we estimated the changes in gas exchange, leaf hydraulic conductance, and leaf turgor in rice (Oryza sativa) in response to both short- and long-term soil drought. We performed a photosynthetic limitation analysis to quantify the contributions of each limiting factor to the resultant overall decrease in photosynthesis during drought. Biomass, leaf area, and leaf width significantly decreased during the 2-week drought treatment, but leaf mass per area and leaf vein density increased. Light-saturated photosynthetic rate declined dramatically during soil drought, mainly due to the decrease in stomatal conductance (gs) and mesophyll conductance (gm). Stomatal modeling suggested that the decline in leaf hydraulic conductance explained most of the decrease in stomatal closure during the drought treatment, and may also trigger the drought-related decrease of stomatal conductance and mesophyll conductance. The results of this study provide insight into the regulation of carbon assimilation under drought conditions.
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Affiliation(s)
- Xiaoxiao Wang
- National Key Laboratory of Crop Genetic Improvement, MOA 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, Hubei, China
| | - Tingting Du
- National Key Laboratory of Crop Genetic Improvement, MOA 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, Hubei, China
| | - Jianliang Huang
- National Key Laboratory of Crop Genetic Improvement, MOA 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, Hubei, China
| | - Shaobing Peng
- National Key Laboratory of Crop Genetic Improvement, MOA 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, Hubei, China
| | - Dongliang Xiong
- National Key Laboratory of Crop Genetic Improvement, MOA 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, Hubei, China
- Department of Plant Sciences, University of California, Davis, CA, USA
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Zhu J, Dai Z, Vivin P, Gambetta GA, Henke M, Peccoux A, Ollat N, Delrot S. A 3-D functional-structural grapevine model that couples the dynamics of water transport with leaf gas exchange. ANNALS OF BOTANY 2018; 121:833-848. [PMID: 29293870 PMCID: PMC5906973 DOI: 10.1093/aob/mcx141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 11/01/2017] [Indexed: 05/03/2023]
Abstract
Background and Aims Predicting both plant water status and leaf gas exchange under various environmental conditions is essential for anticipating the effects of climate change on plant growth and productivity. This study developed a functional-structural grapevine model which combines a mechanistic understanding of stomatal function and photosynthesis at the leaf level (i.e. extended Farqhuhar-von Caemmerer-Berry model) and the dynamics of water transport from soil to individual leaves (i.e. Tardieu-Davies model). Methods The model included novel features that account for the effects of xylem embolism (fPLC) on leaf hydraulic conductance and residual stomatal conductance (g0), variable root and leaf hydraulic conductance, and the microclimate of individual organs. The model was calibrated with detailed datasets of leaf photosynthesis, leaf water potential, xylem sap abscisic acid (ABA) concentration and hourly whole-plant transpiration observed within a soil drying period, and validated with independent datasets of whole-plant transpiration under both well-watered and water-stressed conditions. Key Results The model well captured the effects of radiation, temperature, CO2 and vapour pressure deficit on leaf photosynthesis, transpiration, stomatal conductance and leaf water potential, and correctly reproduced the diurnal pattern and decline of water flux within the soil drying period. In silico analyses revealed that decreases in g0 with increasing fPLC were essential to avoid unrealistic drops in leaf water potential under severe water stress. Additionally, by varying the hydraulic conductance along the pathway (e.g. root and leaves) and changing the sensitivity of stomatal conductance to ABA and leaf water potential, the model can produce different water use behaviours (i.e. iso- and anisohydric). Conclusions The robust performance of this model allows for modelling climate effects from individual plants to fields, and for modelling plants with complex, non-homogenous canopies. In addition, the model provides a basis for future modelling efforts aimed at describing the physiology and growth of individual organs in relation to water status.
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Affiliation(s)
- Junqi Zhu
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Zhanwu Dai
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Philippe Vivin
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Gregory A Gambetta
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Michael Henke
- Department of Ecoinformatics, Biometrics and Forest Growth, University of Göttingen, Göttingen, Germany
| | - Anthony Peccoux
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Nathalie Ollat
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Serge Delrot
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
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Zhang FP, Sussmilch F, Nichols DS, Cardoso AA, Brodribb TJ, McAdam SAM. Leaves, not roots or floral tissue, are the main site of rapid, external pressure-induced ABA biosynthesis in angiosperms. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1261-1267. [PMID: 29340606 PMCID: PMC6018962 DOI: 10.1093/jxb/erx480] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 12/06/2017] [Indexed: 05/21/2023]
Abstract
Rapid biosynthesis of abscisic acid (ABA) in the leaf, triggered by a decrease in cell volume, is essential for a functional stomatal response. However, it is not known whether rapid biosynthesis of ABA is also triggered in other plant tissues. Through the application of external pressure to flower, root, and leaf tissues, we test whether a reduction in cell volume can trigger rapid increases in ABA levels across the plant body in two species, Solanum lycopersicum and Passiflora tarminiana. Our results show that, in contrast to rapid ABA synthesis in the leaf, flower and root tissue did not show a significant, increase in ABA level in response to a drop in cell volume over a short time frame, suggesting that rapid ABA biosynthesis occurs only in leaf, not in flower or root tissues. A gene encoding the key, rate-limiting carotenoid cleavage enzyme (9-cis-epoxycarotenoid dioxygenase, NCED) in the ABA biosynthetic pathway in S. lycopersicum, NCED1, was upregulated to a lesser degree in flowers and roots compared with leaves in response to applied pressure. In both species, floral tissues contained substantially lower levels of the NCED substrate 9'-cis-neoxanthin than leaves, and this ABA precursor could not be detected in roots. Slow and minimal ABA biosynthesis was detected after 2 h in petals, indicating that floral tissue is capable of synthesizing ABA in response to sustained water deficit. Our results indicate that rapid ABA biosynthesis predominantly occurs in the leaves, and not in other tissues.
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Affiliation(s)
- Feng-Ping Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, China
| | - Frances Sussmilch
- Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, Germany
- School of Biological Sciences, University of Tasmania, Australia
| | - David S Nichols
- Central Science Laboratory, University of Tasmania, Australia
| | - Amanda A Cardoso
- School of Biological Sciences, University of Tasmania, Australia
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Campus Universitário, Brasil
| | | | - Scott A M McAdam
- Department of Botany and Plant Pathology and Purdue Center for Plant Biology, Purdue University, USA
- Correspondence:
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Veselov DS, Sharipova GV, Veselov SY, Dodd IC, Ivanov I, Kudoyarova GR. Rapid changes in root HvPIP2;2 aquaporins abundance and ABA concentration are required to enhance root hydraulic conductivity and maintain leaf water potential in response to increased evaporative demand. FUNCTIONAL PLANT BIOLOGY : FPB 2018; 45:143-149. [PMID: 32291028 DOI: 10.1071/fp16242] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/23/2016] [Indexed: 05/13/2023]
Abstract
To address the involvement of abscisic acid (ABA) in regulating transpiration and root hydraulic conductivity (LpRoot) and their relative importance for maintaining leaf hydration, the ABA-deficient barley mutant Az34 and its parental wild-type (WT) genotype (cv. Steptoe) were grown in hydroponics and exposed to changes in atmospheric vapour pressure deficit (VPD) imposed by air warming. WT plants were capable of maintaining leaf water potential (ψL) that was likely due to increased LpRoot enabling higher water flow from the roots, which increased in response to air warming. The increased LpRoot and immunostaining for HvPIP2;2 aquaporins (AQPs) correlated with increased root ABA content of WT plants when exposed to increased air temperature. The failure of Az34 to maintain ψL during air warming may be due to lower LpRoot than WT plants, and an inability to respond to changes in air temperature. The correlation between root ABA content and LpRoot was further supported by increased root hydraulic conductivity in both genotypes when treated with exogenous ABA (10-5 M). Thus the ability of the root system to rapidly regulate ABA levels (and thence aquaporin abundance and hydraulic conductivity) seems important to maintain leaf hydration.
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Affiliation(s)
- Dmitry S Veselov
- Ufa Institute of Biology of Russian Academy of Sciences, pr. Octyabrya, 69, Ufa 450 054, Russia
| | - Guzel V Sharipova
- Ufa Institute of Biology of Russian Academy of Sciences, pr. Octyabrya, 69, Ufa 450 054, Russia
| | | | - Ian C Dodd
- Lancaster Environment Centre, Lancaster University, Bailrigg, Lancashire LA1 4YQ, UK
| | - Igor Ivanov
- Ufa Institute of Biology of Russian Academy of Sciences, pr. Octyabrya, 69, Ufa 450 054, Russia
| | - Guzel R Kudoyarova
- Ufa Institute of Biology of Russian Academy of Sciences, pr. Octyabrya, 69, Ufa 450 054, Russia
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Li W, de Ollas C, Dodd IC. Long-distance ABA transport can mediate distal tissue responses by affecting local ABA concentrations. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2018; 60:16-33. [PMID: 29052969 DOI: 10.1111/jipb.12605] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/16/2017] [Indexed: 05/21/2023]
Abstract
Environmental stresses that perturb plant water relations influence abscisic acid (ABA) concentrations, but it is unclear whether long-distance ABA transport contributes to changes in local ABA levels. To determine the physiological relevance of ABA transport, we made reciprocal- and self-grafts of ABA-deficient flacca mutant and wild-type (WT) tomato plants, in which low phosphorus (P) conditions decreased ABA concentrations while salinity increased ABA concentrations. Whereas foliar ABA concentrations in the WT scions were rootstock independent under conditions, salinity resulted in long-distance transport of ABA: flacca scions had approximately twice as much ABA when grafted on WT rootstocks compared to flacca rootstocks. Root ABA concentrations were scion dependent: both WT and flacca rootstocks had less ABA with the flacca mutant scion than with the WT scion under conditions. In WT scions, whereas rootstock genotype had limited effects on stomatal conductance under conditions, a flacca rootstock decreased leaf area of stressed plants, presumably due to attenuated root-to-shoot ABA transport. In flacca scions, a WT rootstock decreased stomatal conductance but increased leaf area of stressed plants, likely due to enhanced root-to-shoot ABA transport. Thus, long-distance ABA transport can affect responses in distal tissues by changing local ABA concentrations.
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Affiliation(s)
- Wenrao Li
- College of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Carlos de Ollas
- Plant & Crop Sciences, Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, United Kingdom
| | - Ian C Dodd
- Plant & Crop Sciences, Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, United Kingdom
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Males J, Griffiths H. Specialized stomatal humidity responses underpin ecological diversity in C3 bromeliads. PLANT, CELL & ENVIRONMENT 2017; 40:2931-2945. [PMID: 28722113 DOI: 10.1111/pce.13024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 06/26/2017] [Accepted: 07/02/2017] [Indexed: 06/07/2023]
Abstract
The Neotropical Bromeliaceae display an extraordinary level of ecological variety, with species differing widely in habit, photosynthetic pathway and growth form. Divergences in stomatal structure and function, hitherto understudied in treatments of bromeliad evolutionary physiology, could have been critical to the generation of variety in ecophysiological strategies among the bromeliads. Because humidity is a key factor in bromeliad niches, we focussed on stomatal responses to vapour pressure deficit (VPD). We measured the sensitivity of stomatal conductance and assimilation rate to VPD in eight C3 bromeliad species of contrasting growth forms and ecophysiological strategies and parameterised the kinetics of stomatal responses to a step change in VPD. Notably, three tank-epiphyte species displayed low conductance, high sensitivity and fast kinetics relative to the lithophytes, while three xeromorphic terrestrial species showed high conductance and sensitivity but slow stomatal kinetics. An apparent feedforward response of transpiration to VPD occurred in the tank epiphytes, while water-use efficiency was differentially impacted by stomatal closure depending on photosynthetic responses. Differences in stomatal responses to VPD between species of different ecophysiological strategies are closely linked to modifications of stomatal morphology, which we argue has been a pivotal component of the evolution of high diversity in this important plant family.
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Affiliation(s)
- Jamie Males
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Howard Griffiths
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
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Sussmilch FC, McAdam SAM. Surviving a Dry Future: Abscisic Acid (ABA)-Mediated Plant Mechanisms for Conserving Water under Low Humidity. PLANTS (BASEL, SWITZERLAND) 2017; 6:E54. [PMID: 29113039 PMCID: PMC5750630 DOI: 10.3390/plants6040054] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 10/29/2017] [Accepted: 11/01/2017] [Indexed: 12/15/2022]
Abstract
Angiosperms are able to respond rapidly to the first sign of dry conditions, a decrease in air humidity, more accurately described as an increase in the vapor pressure deficit between the leaf and the atmosphere (VPD), by abscisic acid (ABA)-mediated stomatal closure. The genes underlying this response offer valuable candidates for targeted selection of crop varieties with improved drought tolerance, a critical goal for current plant breeding programs, to maximize crop production in drier and increasingly marginalized environments, and meet the demands of a growing population in the face of a changing climate. Here, we review current understanding of the genetic mechanisms underpinning ABA-mediated stomatal closure, a key means for conserving water under dry conditions, examine how these mechanisms evolved, and discuss what remains to be investigated.
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Affiliation(s)
- Frances C Sussmilch
- School of Biological Sciences, University of Tasmania, Hobart TAS 7001, Australia.
- Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, D-97082 Würzburg, Germany.
| | - Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA.
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Sweet KJ, Peak D, Mott KA. Stomatal heterogeneity in responses to humidity and temperature: Testing a mechanistic model. PLANT, CELL & ENVIRONMENT 2017; 40:2771-2779. [PMID: 28777880 DOI: 10.1111/pce.13051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 07/11/2017] [Accepted: 07/30/2017] [Indexed: 06/07/2023]
Abstract
The role of stomatal heterogeneity in the response of stomatal conductance (gs ) to the mole fraction difference in water vapour between the inside of the leaf and the ambient air (Δw) was determined using thermography and gas exchange for 3 species. The value of Δw for the leaf was varied in 2 different ways: first by varying air humidity while holding leaf temperature constant and second by varying leaf temperature while holding air humidity constant. Stomatal heterogeneity was explored by examining the response of gs in small areas of the leaf (as determined by thermography) and comparing them to each other and to the average value of gs (as determined by gas exchange). These analyses show that despite substantial heterogeneity in gs values, the response of gs to Δw was qualitatively similar in all areas of the leaf, and all responses of gs to Δw were well predicted by a recently proposed, vapour-phase mechanism for stomatal responses to temperature and humidity. Remarkably, the 2 model parameters, Θ and Z, that depend on leaf anatomy were constant for a given species, and only the maximum conductance varied in different regions of the leaf.
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Affiliation(s)
- Kathryn J Sweet
- Department of Physics, Utah State University, Logan, UT, 84322, USA
| | - David Peak
- Department of Physics, Utah State University, Logan, UT, 84322, USA
| | - Keith A Mott
- Department of Biology, Utah State University, Logan, UT, 84322, USA
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50
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Qiu C, Ethier G, Pepin S, Dubé P, Desjardins Y, Gosselin A. Persistent negative temperature response of mesophyll conductance in red raspberry (Rubus idaeus L.) leaves under both high and low vapour pressure deficits: a role for abscisic acid? PLANT, CELL & ENVIRONMENT 2017. [PMID: 28620951 DOI: 10.1111/pce.12997] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The temperature dependence of mesophyll conductance (gm ) was measured in well-watered red raspberry (Rubus idaeus L.) plants acclimated to leaf-to-air vapour pressure deficit (VPDL) daytime differentials of contrasting amplitude, keeping a fixed diurnal leaf temperature (Tleaf ) rise from 20 to 35 °C. Contrary to the great majority of gm temperature responses published to date, we found a pronounced reduction of gm with increasing Tleaf irrespective of leaf chamber O2 level and diurnal VPDL regime. Leaf hydraulic conductance was greatly enhanced during the warmer afternoon periods under both low (0.75 to 1.5 kPa) and high (0.75 to 3.5 kPa) diurnal VPDL regimes, unlike stomatal conductance (gs ), which decreased in the afternoon. Consequently, the leaf water status remained largely isohydric throughout the day, and therefore cannot be evoked to explain the diurnal decrease of gm . However, the concerted diurnal reductions of gm and gs were well correlated with increases in leaf abscisic acid (ABA) content, thus suggesting that ABA can induce a significant depression of gm under favourable leaf water status. Our results challenge the view that the temperature dependence of gm can be explained solely from dynamic leaf anatomical adjustments and/or from the known thermodynamic properties of aqueous solutions and lipid membranes..
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Affiliation(s)
- Changpeng Qiu
- Department of Plant Sciences, Laval University, Quebec, Canada
| | - Gilbert Ethier
- Department of Plant Sciences, Laval University, Quebec, Canada
| | - Steeve Pepin
- Department of Soils and Agri-Food Engineering, Laval University, Quebec, Canada
| | - Pascal Dubé
- Institute of Nutrition and Functional Foods (INAF), Laval University, Quebec, Canada
| | - Yves Desjardins
- Department of Plant Sciences, Laval University, Quebec, Canada
| | - André Gosselin
- Department of Plant Sciences, Laval University, Quebec, Canada
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