Study of the Enzymatic Response and Relative Gene Expression of Catalase and Ascorbate Peroxidase to Drought Stress in Barley Plant under Silicon Effect

Various abiotic stresses lead to the overproduction of reactive oxygen species (ROS) in plants and cause to damage to proteins, lipids, carbohydrates and DNA. Antioxidative enzymes such as catalase and ascorbate peroxidase are activated to protect the plants against oxidative stress. Silicon is the second most common element in soil that has beneficial effects in improving plants tolerance to drought stress. Accordingly, the effects of drought stress on semi-quantitative gene expression and enzymatic activities of both catalase and ascorbate peroxidase were investigated in two lines of two-row barley named CB-20315 (resistant) and CB- 20213 (sensitive) in tillering stage in a greenhouse. The experiment was performed in a completely randomized design with three replications for three treatments of control, drought and silicon-drought (sodium silicate 2 mg / 1 kg), and analyzed in factorial experiment. RTPCR semi-quantitative analysis revealed significant differences between treatments. The highest level of gene expression was observed for both enzymes in the silicon-drought treatment. The data showed that silicone application affect antioxidant enzymes activity to increase in both studied lines under drought stress. According to the results of this study it might be concluded that silicon participate in physiological and metabolic changes to enhance plants tolerance to drought stress.