effect of silicon application on physiological characteristics and growth of wheat (triticum aestivum l.) under drought stress condition

in order to investigate the effect of silicon application on some physiological characteristics and growth of wheat (triticum aestivum l.) under late drought stress condition, an experiment was conducted at the agriculture and natural resources university of ramin, khuzestan during year 2012. the experiment was conducted in the open environment as factorial randomized complete block design with three levels of drought stress (irrigation after 25, 50 and 75% depletion of available water content) as the first factor and four levels of silicon (0, 10, 20 and 30 mg si.kg-1 soil) as the second factor with three replications. the results showed that drought stress imposed a negative significant effect on all traits. the drought stress led to increased electrolyte leakage and proline content, cuticular wax, leaf silicon concentration, superoxide dismutase activity (sod) and grain potassium were decreased. the severe drought stress has most effect on electrolyte leakage (up to 53%). the application of silicon except the shoot/root parameter, on all characters have been affected so that application of 30 mg si.kg-1 soil led to decrease electrolyte leakage up to 22.5% and increased sod activity, proline content, cuticular wax grain k and flag leaf si concentration, 25, 12.8, 21, 17 and 30% compared to control, respectively. in general, the results showed a positive effect of silicon on wheat plant under stress conditions that were higher than no stress condition.