Salt‐induced Loss of Potassium From Plant Roots

Abstract

Summary The loss of K+ from excised barley, wheat, chick pea and bean roots was measured in the absence or presence of different concentrations of NaCl and mannitol. In the presence of 50 mM Ca2+, the threshhold NaCl concentration for induction of K+ loss was 160 mM for barley, wheat and chick pea and 140 mm for bean. Mannitol iso‐osmotic to 160 mM NaCl did not induce K+ loss from barley, wheat or chick pea roots indicating that the induction of K+ loss was a salt‐induced and not an osmotic injury. The preventive effect of various concentrations of CaCl2 and MgCl2 on salt‐induced K+loss indicated that the protective effect of Ca2+was specific. Although 50 mM Ca8+ was sufficient, concentrations up to 40 mM may be more effective. The measurement of salt‐induced K+ loss appears to be a quick and reliable method of estimating the degree of salt resistance in plants.

Comparison of inorganic solute accumulation in shoots, radicles and cotyledons ofVicia craccaduring the seedling stage under NaCl stress

“…This finding was similar to that found in wheat embryos (Petruzzelli et al 1991;Cramer et al 1994). Nassery (1979) and Rehman et al (1996) reported that the toxic effect of salts in seeds is usually caused by a reduction in seed K þ concentration. Khan et al (2000) indicated that decreases in endogenous K þ levels induced by high external NaCl concentrations can be attributed to a transmembrane competition between K þ and Na þ fluxes.…”

An Arabidopsis Soil-Salinity–Tolerance Mutation Confers Ethylene-Mediated Enhancement of Sodium/Potassium Homeostasis

“…NaCl is the most soluble and widespread soil salt. High soil Na concentrations damage plants by causing increased tissue Na accumulation and K loss (Nassery, 1979;Greenway and Munns, 1980;Lynch and Läuchli, 1984;Zhu, 2002;Munns and Tester, 2008). Accordingly, plants have evolved a variety of salinity tolerance mechanisms, including mechanisms to restrict Na accumulation and K loss (Zhu, 2002;Smith et al, 2010).…”

Sodium as nutrient and toxicant

“…1a). Upon sudden, "shock", applications of higher concentrations of Na + , membrane disintegrity due to osmotic shock and ionic displacement (particularly of Ca 2+ ), result in the release of cellular contents, including K + and water (Nassery 1975(Nassery , 1979Lynch and Läuchli 1984;Cramer et al 1985;Britto et al 2010;Coskun et al 2013; Fig. 1b), offering an alternative, or additional, explanation of enhanced K + release under Na + exposure (Britto et al 2010;Coskun et al 2013).…”