Effects of salinity on some physiological traits in wheat (Triticum aestivum L.) cultivars

The effect of salt stress on some physiological traits of wheat (Triticum aestivum L.) was studied in a factorial experiment based on completely randomized design with three replications, under greenhouse condition. Salinity treatments carried out in four levels (1.3 dS m-1 as control, 5, 10, 15 dS m-1) via calcium chloride and sodium chloride with 1:10 (Ca2+:Na+ ratio). Wheat genotypes included four cultivars, Sistani and Neishabour as tolerant cultivars, and Tajan and Bahar as sensitive cultivars. Chlorophyll content (CHL), Leaf relative water content (RWC), sodium and potassium contents, and also K+/Na+ ratio were measured at tillering and flowering stages, Total grain yield and yield components were determined. Salinity stress decreased relative water content (RWC), K+ content, K+/Na+ ratio and grain yield; however Na+ content in all the genotypes and in both stages were increased. CHL content increased at tillering stage while it is decreased at flowering stage. Sistani and Neishabour cultivars had more amounts of K+ content, K+/Na+ ratio and RWC under salt conditions, at tillering stage Bahar and Tajan cultivars recorded higher CHL and sodium content at both stages. Bahar showed the highest Na+ content and the most reduction in yield, so it can be considered as more salt sensitive than Tajan genotype. Results showed that the salinity tolerance in tolerant cultivars as manifested by lower decrease in grain yield is associated with the lower sodium accumulation and higher K+/Na+ compared to the sensitive cultivars.