اثر تنش كم آبي و محلول پاشي اسيد آسكوربيك بر ميزان فعاليت آنزيمهاي آنتي اكسيدان و برخي تغييرات بيوشيميايي در برگ ذرت دانه اي (Zea maize L.)

Effect of Water Deficit Stress and Foliar Application of Ascorbic acid on Antioxidants Enzymes Activity and Some BiochemicaFs Changes in Leaves of Grain Corn (Zea maize L.)

Water deficit stress is a common abiotic stress that seriously affects crop production in more parts of the world. Thus, in order to study the effects of water deficit stress and foliar application of ascorbic acid on the activity of some antioxidant enzymes, proline accumulation, lipid peroxidation, protein, chlorophyll, ascorbate and dehydroascorbate contents of grain corn (single cross 704), an experiment was conducted in Faculty of Agronomy of Tarbiat Modares University. Experiment was as a split-split plot in randomized complete block design arrangement with three replications. Water deficit stress was allocated to main plots (before flowering, after flowering and without stress). Ascorbic acid was used at two times (before and after flowering) in sub plot units and four concentrations (0, 50, 100, 150-ppm) in sub-sub plot units. Results showed that water deficit stress increased antioxidant enzymes activity, as this enhancement was remarkably in after flowering stress plots whereas, foliar application of ascorbic acid decreased it. In addition, water deficit stress decreased protein content and chlorophyll concentration in leaves. Proline and malondialdehyde content were increased in response to stress. Ascorbic acid prevented of degradation of protein and chlorophyll of leaves and decreased proline and malondialdehyde in leaves by reduction of water deficit stress. It was observed that cellular ascorbate concentration was increased by exogenous ascorbate application and dehydroascorbate concentration was decreased in water deficit stress treatments particularly in plots which were treated after flowering stress. In addition, plants were preferred ascorbate utilize as a scavenger than the enhancement enzyme activity in against stress. The latter could indirectly decrease enzyme activity and improved growth conditions for plants.