Effect of cadmium toxicity on the level of lipid peroxidation and antioxidative enzymes activity in wheat plants colonized by arbuscular mycorrhizal fungi.

High concentrations of heavy metals in the soil have an adverse effect on micro-organisms and microbial processes. Mycorrhizas are among the extracellular strategies to avoid metal toxicity. In the present study, the effect of cadmium on lipid peroxidation and antioxidative enzymes activity of AM (with Glomus veruciforme, G. intraradices and G. etunicatum) and non-AM Wheat plants was investigated. Wheat plants (Triticum aestivum L. cv. Azar2) which have been colonized by above species, were used in this study. They have been exposed to different concentrations of cadmium chloride for 60 days. The test solution contained: 0 (control), 250, 750 and 2500 microm cadmium Toxicity symptoms such as chlorosis and necrosis appeared on the cadmium treated leaves. Activity of detoxifying enzymes Guaiacol peroxidase (GUPX) and Ascorbate peroxidase (APX) of mycorrhizal and non-mycorrhizal plants were increased. Also, the amount of malondialdehyde (MDA) increased in roots and shoots ofmycorrhizal and non-mycorrhizal plants significantly as a result of Cd treatment, but it was more dramatic in mycorrhizal ones.