Sodium influx and accumulation in Arabidopsis

• Published in: Plant physiology (Bethesda) Vol. 133; no. 1; pp. 307 - 318
• Main Authors: Essah, P.A, Davenport, R, Tester, M
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01-09-2003; American Society of Plant Physiologists
• Subjects: antiporters; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis thaliana; Average linear density; bioaccumulation; Biological and medical sciences; calcium; Calcium - metabolism; calcium channels; Calcium Channels - drug effects; Calcium Channels - metabolism; cation channels; Corn; Diethyl Pyrocarbonate - pharmacology; diethylpyrocarbonate; Environmental Stress and Adaptation; Fundamental and applied biological sciences. Psychology; Hydrogen Peroxide - pharmacology; mutants; Mutation; Osmotic Pressure - drug effects; osmotic treatment; physiological transport; Plant growth; Plant physiology and development; plant proteins; Plant roots; Plant Shoots - genetics; Plant Shoots - growth & development; Plant Shoots - metabolism; Plant Transpiration - drug effects; Plants; Polyethylene Glycols - pharmacology; Potassium Channels - drug effects; Potassium Channels - metabolism; Pretreatment; Protoplasts; Rice; roots; salt stress; Salt tolerance; Sodium; Sodium - metabolism; sodium channels; Sodium Chloride - pharmacology; sodium transporters; soil salinity; Time Factors; transport proteins; uptake mechanisms; Water and solutes. Absorption, translocation and permeability; Arabidopsis thaliana; Phytotoxicity; Sodium; Cruciferae; Dicotyledones; Angiospermae; Biological model; Tolerance; Ion transport; Spermatophyta; Biological accumulation; Salinity
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.103.022178

Arabidopsis is frequently used as a genetic model in plant salt tolerance studies, however, its physiological responses to salinity remain poorly characterized. This study presents a characterization of initial Na+ entry and the effects of Ca2+ on plant growth and net Na+ accumulation in saline conditions. Unidirectional Na+ influx was measured carefully using very short influx times in roots of 12-d-old seedlings. Influx showed three components with distinct sensitivities to Ca2+, diethylpyrocarbonate, and osmotic pretreatment. Pharmacological agents and known mutants were used to test the contribution of different transport pathways to Na+ uptake. Influx was stimulated by 4-aminobutyric acid and glutamic acid; was inhibited by flufenamate, quinine, and cGMP; and was insensitive to modulators of K+ and Ca2+ channels. Influx did not differ from wild type in akt1 and hkt1 insertional mutants. These data suggested that influx was mediated by several different types of nonselective cation channels. Na+ accumulation in plants grown in 50 mM NaCl was strongly reduced by increasing Ca2+ activity (from 0.05-3.0 mM), and plant survival was improved. However, plant biomass was not affected by shoot Na+ concentration, suggesting that in Arabidopsis Na+ toxicity is not dependent on shoot Na+ accumulation. These data suggest that Arabidopsis is a good model for investigation of Na+ transport, but may be of limited utility as a model for the study of Na+ toxicity.