Wheat Response (Triticum aestivum L.) to Selenium under Normal Irrigation and Water Deficit Conditions

To evaluate the effect of selenium (from sodium selenate) on increasing efficiency at water deficit condition a research was conducted in Karaj 1 wheat cultivar in 2014-2015 cropping year with split plot based on completely randomize block design with four replications in Karaj. Irrigation treatments with two levels, normal (I1) and interruption of irrigation at mid flowering (110 days after planting) (I2), which were assigned to main plots and selenium foliar application with six concentrations: 0 (S0), 5 (3.12 micro g.) (S1), 10 (6.24 micro g.) (S2), 15 (9.36 micro g.) (S3), 20 (12.5 micro g.) (S4) and 25 (15.62 micro g,) of sodium selenate per plant (S5) g.ha-1 to sub plots. The results showed that water deficit increased the rate of superoxide dismutase, catalase, glutathione peroxidase and malondialdehyde marker. Foliar application of selenium, increased contents of antioxidant (anti oxidation) enzymes under stress condition and was maximum in 20 g. selenium per ha-1. Content of malondialdehyde was decreased and caused significant increase in grain yield. Increasing antioxidants and reduction of malondialdehyde at normal condition was lower. On the other hand, negative effect of malondialdehyde on yield components, cellular membrane stability and antioxidant enzymes at humidity stress condition was higher than normal condition. Significant increase of cytoplasmic membrane stability, grain yield, grain weight and selenium content of seed was obtained when 15 and 20 g. selenium ha-1 were used as compared with those of higher and lower rates of selenium usage under water deficit and normal irrigation. Suppression of free oxygen radicals, and enzyme induction defense mechanisms against oxidative damage has been effective. Therefore, use of exogenous compounds such as selenium may increase the antioxidant capacity of plant against stress.