Effect of of salinity stress on growth and distribution of tissue-specific ion in wheat (Triticum aestivum L.) cultivars

Salinity is one of the major abiotic stresses that affects physiological functions of plants and significantly reduces crop growth and yield. In this greenhouse experiment, effect of salt stress (Control and 150 mM NaCl) on some physiological traits and ions distribution in roots and leaf 3 blade of four wheat cultivars; Roshan, Bam, Qods and Atrak, and its association with salt tolerance in seedling stage, was studied in a factorial experiment using completely randomized design with three replications during 2014-2015 in College of Agriculture, Shahid Chamran University of Ahvaz, Iran. Results showed that sodium concentration in the roots remains higher than that of the leaf 3 blade. Salt stress significantly decreased stomatal conductance (42%), relative water content (10%), relative growth rate (24%), leaf area (33%), and root length (37%) when compared with the control. Salt-tolerant cultivars, Roshan, Bam and Atrak showed higher stomatal conductance, relative water content, relative growth rate, leaf area and root length in salt treatments when compared to cv. Qods which is salt sensitive. A significant correlation was found between physiological traits and ion distribution in root and leaf blade. Salt-tolerant cultivars sequestered higher sodium concentration in root and higher potassium in leaves. It implies that this ion distribution in root and leaves contributed to the salt tolerance in tolerant cultivars. This preferential sodium accumulation and maintenance in roots relative to shoots can be interpreted as a mechanism of salt tolerance which facilitates osmotic water uptake into the roots and restricts the transportation of sodium to shoots.