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Contrasting water use, stomatal regulation, embolism resistance, and drought responses of two co-occurring mangroves

Citation

Jiang, G-F and Brodribb, TJ and Roddy, AB and Lei, J-Y and Si, H-T and Pahadi, P and Zhang, Y-J and Cao, K-F, Contrasting water use, stomatal regulation, embolism resistance, and drought responses of two co-occurring mangroves, Water, 13, (14) Article 1945. ISSN 2073-4441 (2021) [Refereed Article]


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Copyright Statement

Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons 4.0 International (CC BY 4.0) license (https://creativecommons.org/licenses/by/4.0/).

DOI: doi:10.3390/w13141945

Abstract

The physiological mechanisms underlying drought responses are poorly documented in mangroves, which experience nearly constant exposure to saline water. We measured gas exchange, foliar abscisic acid (ABA) concentration, and vulnerability to embolism in a soil water-withholding experiment of two co-occurring mangroves, Avicennia marina (Forsskål) Vierhapper (Verbenaceae) and Bruguiera gymnorrhiza (L.) Savigny (Rhizophoraceae). A. marina showed higher photosynthesis and transpiration than B. gymnorrhiza under well-watered conditions. Cavitation resistance differed significantly between species, with 50% cavitation occurring at a water potential (P50) of −8.30 MPa for A. marina and −2.83 MPa for B. gymnorrhiza. This large difference in cavitation resistance was associated with differences in stomatal closure and leaf wilting. The rapid stomatal closure of B. gymnorrhiza was correlated with ABA accumulation as water potential declined. Meanwhile, stomatal closure and declining water potentials in A. marina were not associated with ABA accumulation. The safety margins, calculated as the difference between stomatal closure and embolism spread, differed between these two species (1.59 MPa for A. marina vs. 0.52 MPa for B. gymnorrhiza). Therefore, A. marina adopts a drought tolerance strategy with high cavitation resistance, while B. gymnorrhiza uses a drought avoidance-like strategy with ABA-related sensitive stomatal control to protect its vulnerable xylem.

Item Details

Item Type:Refereed Article
Keywords:ABA, cavitation resistance, drought tolerance, hydraulic safety margin, stomatal regulation, gas exchange, salt management strategy
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Ecological physiology
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Australia (excl. social impacts)
UTAS Author:Brodribb, TJ (Professor Tim Brodribb)
ID Code:146711
Year Published:2021
Funding Support:Australian Research Council (DP190101552)
Deposited By:Plant Science
Deposited On:2021-09-22
Last Modified:2021-11-03
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