Effect of exogenous salicylic acid on alleviating lead-induced oxidative stress in leaves of spring canola plants

In this research, the interactive effects of lead (Pb) and salicylic acid (SA) on canola plants were studied. 25-dayold canola plants were exposed to different concentrations of Pb(NO3)2 (0, 250 and 500 μM) and SA (0 and 100 μM) for 10 days. In the absence of SA, excess Pb decreased the dry weight of roots and shoots and reduced chlorophyll content in leaves, while SA moderated these effects. In Pbtreated plants, level of lipoxygenase activity and the contents of malondialdehyde and H2O2 increased, as well as changes in the activities of the antioxidant enzymes, catalase, guaiacol peroxidase and superoxide dismutase, in leaves indicated that Pb caused an oxidative stress in canola plants. Addition of SA together with Pb ions significantly increased the activity of antioxidant enzymes and reduced H2O2 content and the level of lipid peroxidation in leaves. SA also decreased root-to-shoot translocation of Pb in plants under Pb stress. Consequently, salicylic acid by sequestration of Pb in roots and with an increase in the activities of antioxidant enzymes markedly reduced Pb-induced oxidative damage on canola plants.

Keywords:

Lead , Oxidative stress , Salicylic acid , Canola