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Differential tolerance to combined salinity and O2 deficiency in the halophytic grasses Puccinellia ciliata and Thinopyrum ponticum: the importance of K+ retention in roots

Citation

Teakle, NL and Bazihizina, N and Shabala, S and Colmer, TD and Barrett-Lennard, EG and Rodrigo-Moreno, A and Lauchli, AE, Differential tolerance to combined salinity and O2 deficiency in the halophytic grasses Puccinellia ciliata and Thinopyrum ponticum: the importance of K+ retention in roots, Environmental and Experimental Botany, 87 pp. 69-78. ISSN 0098-8472 (2013) [Refereed Article]

Copyright Statement

Copyright 2012 Elsevier B.V.

DOI: doi:10.1016/j.envexpbot.2012.09.006

Abstract

Saline environments of terrestrial halophytes are often prone to waterlogging, yet the effects on halophytes of combined salinity and waterlogging have rarely been studied. Either salinity or hypoxia (low O2) alone can interfere with K+ homeostasis, therefore the combination of salinity or hypoxia is expected to impact significantly on K+ retention in roots. We studied mechanisms of tolerance to the interaction of salinity with hypoxia in Puccinellia ciliata and Thinopyrum ponticum, halophytic grasses that differ in waterlogging tolerance. Plants were exposed to aerated and stagnant saline (250 mM NaCl) treatments with low (0.25 mM) and high (4 mM) K+ levels; growth, net ion fluxes and tissue ion concentrations were determined. P. ciliata was more tolerant than T. ponticum to stagnant-saline treatment, producing twice the biomass of adventitious roots, which accumulated high levels of Na+, and had lower shoot Na+. After 24 h of saline hypoxic treatment, MIFE measurements revealed a net uptake of K+ (~40 nmol m−2 s−1) for P. ciliata, but a net loss of K+ (~20 nmol m−2 s−1) for the more waterlogging sensitive T. ponticum. NaCl alone induced K+ efflux from roots of both species, with channel blocker tests implicating GORK-like channels. P. ciliata had constitutively a more negative root cell membrane potential than T. ponticum (−150 versus −115 mV). Tolerance to salinity and hypoxia in P. ciliata is related to increased production of adventitious roots, regulation of shoot K+/Na+, and a superior ability to maintain negative membrane potential in root cells, resulting in greater retention of K+.

Item Details

Item Type:Refereed Article
Keywords:adventitious roots, halophytes, membrane potential, potassium, sodium, waterlogging
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Environmentally Sustainable Plant Production
Objective Field:Environmentally Sustainable Plant Production not elsewhere classified
Author:Shabala, S (Professor Sergey Shabala)
Author:Rodrigo-Moreno, A (Ms Ana Rodrigo Moreno)
ID Code:82117
Year Published:2013
Web of Science® Times Cited:19
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2013-01-16
Last Modified:2014-04-09
Downloads:0

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