Salinity effects on compatible solutes, antioxidants enzymes and ion content in three wheat cultivars.

In order to study effects of different salinity levels on antioxidant enzyme activities, catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX) associated with compatible solutes, proline and carbohydrate and mineral nutrient content in shoots, sodium and potassium, in three wheat cultivars an experiment was conducted as completely randomized 3 x 4 factorial design with three replicates in a greenhouse. Three wheat cultivars (Pishtaz, Kavir and Hamon), that differ in their salt tolerances, were grown in four different salinity levels (S0 = control, S1 = 100, S2 = 200 and S3 = 300 mM NaCl). Twenty days after wheat cultivars subjected to salt stress, data showed salinity stress induced increase in the antioxidant enzyme activities. Among the cultivars, salinity stress decreased leaf-APX but increased the activities of leaf-GPX in Pishtaz cultivar. Our results showed a positive correlation between praline accumulation and Leaf-APX (r2 = 0.56), Leaf-GPX (r2 = 0.63) and Leaf-CAT (r2 = 0.73). In these cultivars, in their shoots Na+ showed an increase in concentration with salinity that approximately matches a decrease in K+ concentration. It seems that Na+ concentrations in the shoot may have had a more significant effect on plant antioxidant enzyme activities and compatible solutes such as proline and carbohydrates. These results indicated which in wheat under salinity stress antioxidant enzymes and compatible solutes help to plant adaptation. In this study we found a positive correlation between Na+ concentration in the shoots and the antioxidant enzyme activities and compatible solutes in the leaves.