Ameliorative Effects of Nitric Oxide on Oilseed Rape (Brassica napus L.) Under Water Stress

The ameliorative effects of nitric oxide on oilseed rape seedlings, Okapy cultivar, under drought condition were investigated. Water stress at 60 and 30% field capacity, increased lipid peroxidation and H2O2 content in oilseed rape leaves. Among the different concentrations (25, 50, 75 and 100 mu M) of sodium nitroprusside used, spraying plants leaves with 25 mu M sodium nitroprusside a NO donor, reduced the damaging effects of water stress which was reflected by a decrease in malondialdehyde and hydrogen peroxide content in leaves. Drought stress enhanced leaves superoxide dismutase, peroxidase and ascorbate peroxidase activities but decreased catalase activity. Sodium nitroprusside treatment (25 mu M) had a positive effect on antioxidant enzymes under water stress. At higher sodium nitroprusside concentrations, its ameliorative effects on water stress were decreased and the oxidative damages to the leaves were sustained. The reduction in drought induced oxidative damages by NO in oilseed rape is most likely mediated by the NO ability to induce and increase the activity of reactive oxygen species scavenging enzymes.