Effect of silicon in increasing drought tolerance on 2-leaves stage of barley plant

In the present study, drought-induced changes in some antioxidant enzyme activities (catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX) and superoxide dismutase (SOD)), total soluble protein content, chlorophyll, proline and glycine betaine were investigated in two barley (Hordeum vulgare L.) cultivars differed in drought tolerance condition, namely Kavir (toleran) and Jonub (sensitive) with or without silicon. A factorial experiment was performed in a completely randomized design with three replications for three treatments (Control, Drought, Drought silicon). According to variance analysis, all simple and contrast factors effect were significantly meaningful except treatment × cultivar contrast effect of peroxidase. The results show that application of silicon was induced to increase antioxidant enzymes activities and osmolytes in both cultivars under drought stress condition. The contents of chlorophyll and total soluble protein were significantly decreased by drought on both cultivars, whereas application of silicon approximately compensated such decrease. Generally, all studied activities of treatments were higher in the tolerant cultivar than the sensitive. It might be concluded that silicon is caused to increase antioxidant enzyme activities to elevate drought tolerance in both cultivars. Therefore, silicon may be involved in metabolic or physiological activities in higher plants under stress.