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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
journal contribution
posted on 2023-05-17, 15:25 authored by Teakle, NL, Bazihizina, N, Sergey ShabalaSergey Shabala, Colmer, TD, Barrett-Lennard, EG, Rodrigo-Moreno, A, Lauchli, AESaline 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+.
History
Publication title
Environmental and Experimental BotanyVolume
87Pagination
69-78ISSN
0098-8472Department/School
Tasmanian Institute of Agriculture (TIA)Publisher
Elsevier BVPlace of publication
Radarweg 29,PO Box 211Amsterdam,1000 AE NetherlandRights statement
Copyright 2012 Elsevier B.V.Repository Status
- Restricted