Stem girdling uncouples soybean stomatal conductance from leaf water potential by enhancing leaf xylem ABA concentration

Castro Valdecantos, Pedro and Puertolas Simon, Jaime and Dodd, Ian Charles (2019) Stem girdling uncouples soybean stomatal conductance from leaf water potential by enhancing leaf xylem ABA concentration. Environmental and Experimental Botany, 159. pp. 146-156. ISSN 0098-8472

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To understand the impact of shoot-to-root ABA transport on water potential of, and xylem ABA concentration in, different plant tissues during soil drying, soybean (Glycine max cv. Siverka) plants were subjected to drought and girdling in a factorial experiment. Girdling was achieved by surgically excising the phloem tissue from just above the cotyledonary node. After girdling and withholding water, ABA concentrations were determined in xylem saps extracted from individual leaves, detached shoots and de-topped roots, after measuring stomatal conductance (gs), tissue water potentials, and root ABA concentrations. Soil drying decreased water potential throughout the plant and approximately doubled xylem ABA concentrations, coinciding with stomatal closure. Girdling slightly enhanced water potential, especially in droughted plants. Girdling diminished the soil-drying induced increase in xylem sap ABA concentration, and completely prevented root tissue ABA accumulation. Furthermore, girdling decreased root ABA concentration and increased leaf xylem ABA concentration of well-watered (WW) plants. Stomatal conductance declined linearly with leaf water potential only in intact plants, while gs declined as leaf xylem ABA concentration increased, independently of girdling. Thus shoot to root ABA transport not only determines (soil-drying induced) root ABA accumulation, but also limits ABA accumulation in the shoot to maintain stomatal opening of WW plants.

Item Type:
Journal Article
Journal or Publication Title:
Environmental and Experimental Botany
Additional Information:
This is the author’s version of a work that was accepted for publication in Environmental and Experimental Botany. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Environmental and Experimental Botany, 159, 2019 DOI: 10.1016/j.envexpbot.2018.12.020
Uncontrolled Keywords:
?? gas exchangewater statusaba transportwater stressplant scienceecology, evolution, behavior and systematicsagronomy and crop science ??
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Deposited On:
08 Jan 2019 14:05
Last Modified:
16 Dec 2023 01:28