evaluation of some of biochemical and physiological traits in wheat cultivars in response to salinity stress at seedling stage

in order to evaluate the physiological and biochemical traits in response to salinity, six varieties of wheat were cultivated in a split plot based on randomized complete block design in the growth chamber in the department of agronomy, faculty of agriculture, university of maragheh. seedlings of wheat cultivars, in three to four leaves stage were treated with 200 mm nacl for 14 days. after the elapsed mentioned time, the activity of some antioxidant enzymes, oxidative stress indices and some physiological parameters were measured. the results showed that lipid peroxidation in all cultivars except augusta significantly increased compared to controls. salinity reduces membrane stability index in cultivars. while the mentioned index was stable and did not change significantly in both environments in other cultivars. ascorbate peroxidase and catalase activities showed a significant decrease in koohdasht, pishtaz and mv17 cultivars under salt stress in comparison with the control. but salinity increased ascorbate peroxidase activity and decreased catalase activity in ayzngran. guaicul peroxidase activity was reduced by salinity only in augusta. glutathione s -transferase only increased in gaskogen and kohdasht and pishtaz cultivars had decreased significantly. moreover, the results showed that, despite the increase in sodium uptake by the roots of all cultivars, only ayzngran and augusta had the ability to transfer control of sodium to crown and leaves. moreover, among cultivars studied, salinity significantly reduced the total dry weight per plant of kohdasht. as a final result can be stated, although sodium is toxic element for cell metabolism, especially the leaf cells, but if the increased activity of antioxidant enzymes with the ability to store this element, except in areas cytocell, would reduce the toxicity of this element, even wheat variety is not able to prevent the transmission of sodium to leaves.