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Castro-Valdecantos P, Puértolas J, Dodd IC. Similar soil drying-induced stomatal closure in soybean genotypes varying in abscisic acid accumulation and stomatal sensitivity to abscisic acid. FUNCTIONAL PLANT BIOLOGY : FPB 2024; 51:NULL. [PMID: 37072870 DOI: 10.1071/fp23012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/21/2023] [Indexed: 05/03/2023]
Abstract
Different soybean cultivars (Williams 82 , Union , Jindou 21 , Long Huang 1 , Long Huang 2 ) were exposed to drying soil, to investigate whether endogenous abscisic acid (ABA) concentrations and leaf water relations regulated stomatal behaviour. We measured ABA concentrations in xylem and tissue of the first and second trifoliate leaves respectively; stomatal conductance (gs ) and leaf water potential (Ψleaf ) in both leaves; and water content in soil. Cultivar variation in leaf area and g s caused different rates of soil drying, but g s and Ψ leaf declined similarly with soil drying in all cultivars. Variation in leaf xylem ABA concentration better explained stomatal responses than foliar ABA concentration in some cultivars, and was highly correlated with stomatal conductance. Xylem ABA concentration in well-watered soil was highest in Union , and in drying soil was lowest in Jindou 21 and Long Huang 2 , although the latter had the highest foliar ABA concentrations. Jindou 21 accumulated lower xylem ABA concentrations than other cultivars as soil moisture or Ψ leaf decreased, but its stomatal sensitivity to xylem ABA was greater. Because cultivars varied in both ABA accumulation and stomatal sensitivity to ABA, but had similar stomatal sensitivity to Ψ leaf , leaf water relations seem more important in regulating stomatal closure of soybean.
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Affiliation(s)
- Pedro Castro-Valdecantos
- Lancaster Environment Centre, Lancaster LA1 4YQ, UK; and School of Life Sciences and Centre for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Sha Tin, Hong Kong, China; and The Joint Institute for the Environmental Research and Education, Guangzhou, China; and Present address: Department of Agronomy, Escuela Técnica Superior de Ingeniería Agronómica, University of Seville, Ctra. Utrera km. 1, Seville 41013, Spain
| | - Jaime Puértolas
- Lancaster Environment Centre, Lancaster LA1 4YQ, UK; and Present address: Department of Botany and Plant Ecology and Physiology, University of La Laguna, Facultad de Farmacia, Avd Astrofísico Francisco Sánchez s/n, San Cristóbal de La Laguna, Canary Islands 38200, Spain
| | - Ian C Dodd
- Lancaster Environment Centre, Lancaster LA1 4YQ, UK; and The Joint Institute for the Environmental Research and Education, Guangzhou, China
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Saradadevi R, Palta JA, Siddique KHM. ABA-Mediated Stomatal Response in Regulating Water Use during the Development of Terminal Drought in Wheat. FRONTIERS IN PLANT SCIENCE 2017; 8:1251. [PMID: 28769957 PMCID: PMC5513975 DOI: 10.3389/fpls.2017.01251] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 07/03/2017] [Indexed: 05/19/2023]
Abstract
End-of-season drought or "terminal drought," which occurs after flowering, is considered the most significant abiotic stress affecting crop yields. Wheat crop production in Mediterranean-type environments is often exposed to terminal drought due to decreasing rainfall and rapid increases in temperature and evapotranspiration during spring when wheat crops enter the reproductive stage. Under such conditions, every millimeter of extra soil water extracted by the roots benefits grain filling and yield and improves water use efficiency (WUE). When terminal drought develops, soil dries from the top, exposing the top part of the root system to dry soil while the bottom part is in contact with available soil water. Plant roots sense the drying soil and produce signals, which on transmission to shoots trigger stomatal closure to regulate crop water use through transpiration. However, transpiration is linked to crop growth and productivity and limiting transpiration may reduce potential yield. While an early and high degree of stomatal closure affects photosynthesis and hence biomass production, a late and low degree of stomatal closure exhausts available soil water rapidly which results in yield losses through a reduction in post-anthesis water use. The plant hormone abscisic acid (ABA) is considered the major chemical signal involved in stomatal regulation. Wheat genotypes differ in their ability to produce ABA under drought and also in their stomatal sensitivity to ABA. In this viewpoint article we discuss the possibilities of exploiting genotypic differences in ABA response to soil drying in regulating the use of water under terminal drought. Root density distribution in the upper drying layers of the soil profile is identified as a candidate trait that can affect ABA accumulation and subsequent stomatal closure. We also examine whether leaf ABA can be designated as a surrogate characteristic for improved WUE in wheat to sustain grain yield under terminal drought. Ease of collecting leaf samples to quantify ABA compared to extracting xylem sap will facilitate rapid screening of a large number of germplasm for drought tolerance.
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Affiliation(s)
- Renu Saradadevi
- School of Agriculture and Environment, The University of Western Australia, PerthWA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, PerthWA, Australia
| | - Jairo A. Palta
- School of Agriculture and Environment, The University of Western Australia, PerthWA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, PerthWA, Australia
- CSIRO Agriculture and Food, WembleyWA, Australia
| | - Kadambot H. M. Siddique
- School of Agriculture and Environment, The University of Western Australia, PerthWA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, PerthWA, Australia
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Boyle RKA, McAinsh M, Dodd IC. Stomatal closure of Pelargonium × hortorum in response to soil water deficit is associated with decreased leaf water potential only under rapid soil drying. PHYSIOLOGIA PLANTARUM 2016; 156:84-96. [PMID: 25974219 DOI: 10.1111/ppl.12346] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 04/12/2015] [Indexed: 06/04/2023]
Abstract
Soil water deficits applied at different rates and for different durations can decrease both stomatal conductance (gs ) and leaf water potential (Ψleaf ). Understanding the physiological mechanisms regulating these responses is important in sustainable irrigation scheduling. Glasshouse-grown, containerized Pelargonium × hortorum BullsEye plants were irrigated either daily at various fractions of plant evapotranspiration (100, 75 and 50% ET) for 20 days or irrigation was withheld for 4 days. Xylem sap was collected and gs and Ψleaf were measured on days 15 and 20, and on days 16-19 for the respective treatments. Xylem sap pH and NO3 (-) and Ca(2+) concentrations did not differ between irrigation treatments. Xylem abscisic acid (ABA) concentrations ([ABA]xyl ) increased within 24 h of irrigation being withheld whilst gs and Ψleaf decreased. Supplying irrigation at a fraction of daily ET produced a similar relationship between [ABA]xyl and gs , but did not change Ψleaf . Treatment differences occurred independently of whether Ψleaf was measured in whole leaves with a pressure chamber, or in the lamina with a thermocouple psychrometer. Plants that were irrigated daily showed lower [ABA]xyl than plants from which irrigation was withheld, even at comparable soil moisture content. This implies that regular re-watering attenuates ABA signaling due to maintenance of soil moisture in the upper soil levels. Crucially, detached leaves supplied with synthetic ABA showed a similar relationship between [ABA]xyl and gs as intact plants, suggesting that stomatal closure of P. hortorum in response to soil water deficit is primarily an ABA-induced response, independent of changes in Ψleaf .
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Affiliation(s)
- Richard K A Boyle
- The Lancaster Environment Centre, Lancaster University, Lancaster, Lancashire, LA1 4YQ, UK
| | - Martin McAinsh
- The Lancaster Environment Centre, Lancaster University, Lancaster, Lancashire, LA1 4YQ, UK
| | - Ian C Dodd
- The Lancaster Environment Centre, Lancaster University, Lancaster, Lancashire, LA1 4YQ, UK
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Pérez-Pérez JG, Dodd IC. Sap fluxes from different parts of the rootzone modulate xylem ABA concentration during partial rootzone drying and re-wetting. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2315-24. [PMID: 25740924 PMCID: PMC4407653 DOI: 10.1093/jxb/erv029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/04/2014] [Accepted: 01/09/2015] [Indexed: 05/09/2023]
Abstract
Previous studies with partial rootzone drying (PRD) irrigation demonstrated that alternating the wet and dry parts of the rootzone (PRD-Alternated) increased leaf xylem ABA concentration ([X-ABA]leaf) compared with maintaining the same wet and dry parts of the rootzone (PRD-Fixed). To determine the relative contributions of different parts of the rootzone to this ABA signal, [X-ABA]leaf of potted, split-root tomato (Solanum lycopersicum) plants was modelled by quantifying the proportional water uptake from different soil compartments, and [X-ABA]leaf responses to the entire pot soil-water content (θpot). Continuously measuring soil-moisture depletion by, or sap fluxes from, different parts of the root system revealed that water uptake rapidly declined (within hours) after withholding water from part of the rootzone, but was rapidly restored (within minutes) upon re-watering. Two hours after re-watering part of the rootzone, [X-ABA]leaf was equally well predicted according to θpot alone and by accounting for the proportional water uptake from different parts of the rootzone. Six hours after re-watering part of the rootzone, water uptake by roots in drying soil was minimal and, instead, occurred mainly from the newly irrigated part of the rootzone, thus [X-ABA]leaf was best predicted by accounting for the proportional water uptake from different parts of the rootzone. Contrary to previous results, alternating the wet and dry parts of the rootzone did not enhance [X-ABA]leaf compared with PRD-Fixed irrigation. Further work is required to establish whether altered root-to-shoot ABA signalling contributes to the improved yields of crops grown with alternate, rather than fixed, PRD.
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Affiliation(s)
- J G Pérez-Pérez
- Department of Citriculture, IMIDA, 30150 La Alberca, Murcia, Spain
| | - I C Dodd
- Centre for Sustainable Agriculture, Lancaster Environment Centre, University of Lancaster, Lancaster LA1 4YQ, Uk
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Dodd IC, Theobald JC, Richer SK, Davies WJ. Partial phenotypic reversion of ABA-deficient flacca tomato (Solanum lycopersicum) scions by a wild-type rootstock: normalizing shoot ethylene relations promotes leaf area but does not diminish whole plant transpiration rate. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:4029-39. [PMID: 19648172 PMCID: PMC2755025 DOI: 10.1093/jxb/erp236] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 07/03/2009] [Accepted: 07/06/2009] [Indexed: 05/19/2023]
Abstract
To evaluate the role of root-synthesized ABA in regulating growth and stomatal behaviour under well-watered conditions, isogenic wild-type (WT) and ABA-deficient flacca (flc) tomato (Solanum lycopersicum) were reciprocally and self-grafted just below the cotyledonary node. Since flc scions had lower leaf water potentials due to higher transpiration rates, a subset of all graft combinations was grown under a shoot misting treatment to minimize differences in shoot water status. Misting did not alter the relative effects of the different graft combinations on leaf area. WT scions had the greatest leaf area and lowest whole plant transpiration rate irrespective of the rootstock, implying that shoot ABA biosynthesis was sufficient to account for a WT shoot phenotype. In WT scions, the rootstock had no effect on detached leaf ethylene evolution or xylem concentrations of ABA or the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC). In flc scions, although the WT rootstock suppressed stomatal conductance of individual leaves, there was no detectable effect on whole plant transpiration rate. However, leaf area of flc/WT (scion/rootstock) plants increased 1.6-fold compared to flc self-grafts. WT rootstocks increased xylem ABA concentration in flc scions (relative to flc self-grafts) up to 3-fold, and resulted in xylem ACC concentrations and detached leaf ethylene evolution similar to WT scions. Since the WT rootstock normalized shoot ethylene relations but only partially restored the leaf area of flc scions (relative to that of WT scions), shoot ABA biosynthesis can directly promote leaf area via an unknown, ethylene-independent, mechanism.
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Affiliation(s)
- Ian C Dodd
- The Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
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Dodd IC. Soil moisture heterogeneity during deficit irrigation alters root-to-shoot signalling of abscisic acid. FUNCTIONAL PLANT BIOLOGY : FPB 2007; 34:439-448. [PMID: 32689371 DOI: 10.1071/fp07009] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 03/06/2007] [Indexed: 06/11/2023]
Abstract
The effects of different irrigation techniques on leaf xylem ABA concentration ([X-ABA]leaf) were compared in tomato (Lycopersicon esculentum Mill.). During partial rootzone drying (PRD), water was distributed unevenly to the root system such that part was irrigated while the remainder was allowed to dry the soil. During conventional deficit irrigation (DI), plants received the same volume of water as PRD plants, but water was distributed evenly to the entire root system. When the plant root system was allowed to explore two separate soil compartments, DI plants had a higher [X-ABA]leaf than PRD plants with moderate soil drying, but PRD plants had a higher [X-ABA]leaf than DI plants as the soil dried further. The difference in [X-ABA]leaf between the two sets of plants was not because of differences in either whole pot soil water content (θpot) or leaf water potential (Ψleaf). To investigate the contribution of different parts of the root system to [X-ABA]leaf, individual shoots were grafted onto the root systems of two plants grown in two separate pots, so that the graft union had the appearance of an inverted 'Y'. After sap collection from detached leaves, removal of the shoot below the graft union allowed sap collection from each root system. Again, DI plants had a higher [X-ABA]leaf than PRD plants when the soil was relatively wet, but the opposite occurred as the soil dried. Root xylem ABA concentration ([X-ABA]root) increased exponentially as soil water content (θ) declined. In DI plants, [X-ABA]root from either pot (or the arithmetic mean of [X-ABA]root) accounted for a similar amount of the variation in [X-ABA]leaf. In PRD plants, [X-ABA]root from the watered side underestimated [X-ABA]leaf, whereas [X-ABA]root from the dry side overestimated [X-ABA]leaf. The arithmetic mean of [X-ABA]root best explained the variation in [X-ABA]leaf, implying continued sap flow from the dry part of the root system (Jdry) at soil water potentials (Ψsoil) at which Jdry had ceased in previous studies of PRD plants (Yao et al. 2001). Evaluating the relationship between Jdry and Ψsoil may assist in maintaining export of ABA (and other growth regulators) from the drying part of the root system, to achieve desirable horticultural outcomes during PRD.
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Affiliation(s)
- Ian C Dodd
- The Lancaster Environment Centre, Lancaster University, LA1 4YQ, UK. Email
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Azedo-Silva J, Osório J, Fonseca F, Correia MJ. Effects of soil drying and subsequent re-watering on the activity of nitrate reductase in roots and leaves of Helianthus annuus. FUNCTIONAL PLANT BIOLOGY : FPB 2004; 31:611-621. [PMID: 32688933 DOI: 10.1071/fp04018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Accepted: 03/16/2004] [Indexed: 05/10/2023]
Abstract
The effects of drought on the activity of nitrate reductase (NR) were studied in Helianthus annuus L. plants subjected to soil drying and subsequent re-watering. Drought did not negatively affect the activation state of NR, but resulted in linearly-correlated decreases in the activity of the unphosphorylated active form and the total activity of NR, in both roots and leaves. The concentration of nitrate in roots, xylem and leaves also decreased in water-stressed plants, whereas the concentration of total amino acids was only transiently depressed at the leaf level. In contrast, soluble sugars accumulated both in roots and leaves of water-stressed plants. Drought-induced decreases in root NR activity were correlated with the observed changes in root nitrate concentration. A higher percentage of the decrease in foliar NR activity could be explained by the decline in nitrate flux to the leaves than by leaf nitrate content. Following re-watering, the extent of recovery of NR activity was higher in roots than in leaves. The delay in the recovery of foliar NR activity did not result from the persistence of reduced flux of nitrate through the xylem. Several hypotheses to explain the after-effect of soil drying on foliar NR activity are discussed.
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Affiliation(s)
- João Azedo-Silva
- Universidade do Algarve, CDCTPV, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Júlio Osório
- Universidade do Algarve, CDCTPV, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Filomena Fonseca
- Universidade do Algarve, CDCTPV, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Maria João Correia
- Universidade do Algarve, CDCTPV, Campus de Gambelas, 8005-139 Faro, Portugal
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