SODIUM AND CHLORIDE-IONS CONTRIBUTE SYNERGISTICALLY TO SALT TOXICITY IN WHEAT

The effects of supplying excess mineral salts, involving sodium as a c ation and a range of counteranions, including chloride, on the growth and photosynthetic capacity of a salt susceptible bread wheat were stu died. Plant performance was much more affected by the NaCl treatment t han by the same concentration of either of the two component ions. Wit h the exception of K+, other alkali metal chlorides also greatly inhib it plant growth and the electron flow through photosystem 2. The ranki ng of toxicity of these cations is Li+ > Na+ > K+. The synergistic eff ect of sodium (and other alkali and alkaline earth metals) and chlorid e shows that neither of these ions alone is responsible for salt stres s induced damage.