Coordinated decline of leaf hydraulic and stomatal conductances under drought is not linked to leaf xylem embolism for different grapevine cultivars

Bibliographische Detailangaben
Veröffentlicht in:	Journal of experimental botany. - 1985. - 71(2020), 22 vom: 31. Dez., Seite 7286-7300
1. Verfasser:	Albuquerque, Caetano (VerfasserIn)
Weitere Verfasser:	Scoffoni, Christine, Brodersen, Craig R, Buckley, Thomas N, Sack, Lawren, McElrone, Andrew J
Format:	Online-Aufsatz
Sprache:	English
Veröffentlicht:	2020
Zugriff auf das übergeordnete Werk:	Journal of experimental botany
Schlagworte:	Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Vitis Anatomy drought ecophysiology gas exchange leaf hydraulics micro-CT mehr... modeling Water 059QF0KO0R

Beschreibung
Zusammenfassung:	© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissionsoup.com. Drought decreases water transport capacity of leaves and limits gas exchange, which involves reduced leaf leaf hydraulic conductance (Kleaf) in both the xylem and outside-xylem pathways. Some literature suggests that grapevines are hyper-susceptible to drought-induced xylem embolism. We combined Kleaf and gas exchange measurements, micro-computed tomography of intact leaves, and spatially explicit modeling of the outside-xylem pathways to evaluate the role of vein embolism and Kleaf in the responses of two different grapevine cultivars to drought. Cabernet Sauvignon and Chardonnay exhibited similar vulnerabilities of Kleaf and gs to dehydration, decreasing substantially prior to leaf xylem embolism. Kleaf and gs decreased by 80% for both cultivars by Ψ leaf approximately -0.7 MPa and -1.2 MPa, respectively, while leaf xylem embolism initiated around Ψ leaf = -1.25 MPa in the midribs and little to no embolism was detected in minor veins even under severe dehydration for both cultivars. Modeling results indicated that reduced membrane permeability associated with a Casparian-like band in the leaf vein bundle sheath would explain declines in Kleaf of both cultivars. We conclude that during moderate water stress, changes in the outside-xylem pathways, rather than xylem embolism, are responsible for reduced Kleaf and gs. Understanding this mechanism could help to ensure adequate carbon capture and crop performance under drought
Beschreibung:	Date Completed 14.05.2021 Date Revised 14.05.2021 published: Print Citation Status MEDLINE
ISSN:	1460-2431
DOI:	10.1093/jxb/eraa392