Abstract

The jasmonates are a group of plant–growth regulators that cause a wide variety of plant responses. Cadmium (Cd) is a toxic heavy metal, which causes toxicity in living organisms, and is considered as an environmental contaminant. In present investigation, the interactive effects of methyl jasmonate (0, 0.01 or 0.1 mM) and cadmium chloride (0 or 500 µM) on malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and antioxidant enzymes in soybean (Glycine max L.) leaves were studied. Treatment of methyl jasmonate (MeJA) together with cadmium reduced the amount of H₂O₂ and MDA when compared with cadmium treated plants. The activity of superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT), increased in treated plants with MeJA, and Cd, but guaiacol peroxidase (GPX) activity did not show any noticeable difference. In addition, MeJA treatment increased the amount of dehydro ascorbic acid (DHA) in plants under Cd stress whereas, there was no significant difference in the content of ascorbic acid (ASA). Based on our results, it seems that the application of MeJA together with Cd caused alleviation of Cd damages by the reduction of MDA and H₂O₂ content and increase in activities of antioxidant enzymes in soybean plants.

Key words: Ascorbate peroxidase, catalase, lipid peroxidation, superoxide dismutase.