Displacement of Ca2+ by Na+ from the Plasmalemma of Root Cells: A Primary Response to Salt Stress?
Year: 1985
Type: article
Abstract: A microfluorometric assay using chlorotetracycline (CTC) as a probe for membrane-associated Ca(2+) in intact cotton (Gossypium hirsutum L. cv Acala SJ-2) root hairs indicated displacement of Ca(2+) by Na(+) from membrane sites with increasing levels of NaCl (0 to 250 millimolar). K(+)((86)Rb) efflux increased dramatically at high salinity. An increase in external Ca(2+) concentration (10 millimolar) mitigated both responses. Other cations and mannitol, which did not affect Ca(2+)-CTC chelation properties, were found to have no effect on Ca(2+)-CTC fluorescence, indicating a Na(+)-specific effect. Reduction of Ca(2+)-CTC fluorescence by ethyleneglycol-bis-(beta-aminoethyl ether) N,N'-tetraacetic acid, which does not cross membranes, provided an indication that reduction by Na(+) of Ca(2+)-CTC fluorescence may be occurring primarily at the plasmalemma. The findings support prior proposals that Ca(2+) protects membranes from adverse effects of Na(+) thereby maintaining membrane integrity and minimizing leakage of cytosolic K(+).
Source: PLANT PHYSIOLOGY
DOI: 10.1104/pp.79.1.207
Authors: Grant R. Cramer, André Läuchli, Vito S. Polito
Institution: University of California, Davis
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2167917677