Effect of mycorrhizal fungus on growth and physiological parameters of sunflower and safflower under Cd stress.

A greenhouse experiment with potted plants was conducted to study the effect of arbuscular mycorrhiza (Glomus intraradices) fungal inoculation on The growth, cadmium concentration and The activates of antioxidant enzymes (Superoxide Dismutase (SOD) and Catalase (CAT)) in sunflower and safflower in four levels of Cd (0, 2.5, 5 and 25 mg Cd kg-1 soil). Treatment were arranged in the experiment factorial in a completely randomized design with three replications. In this study, exposure to Cd decreased the root and shoot dry weight of both plants and CAT activity in safflower but increased root and shoot concentrations, SOD activity in both plants and the activity of CAT only in sunflower. Inoculation of both plants with AM fungi significantly increased root and shoot dry weights, shoot Cd concentration in sunflower shoot and CAT activity in safflower as compared to non-mycorrhizal plants. However, inoculation decreased Cd concentration in root and SOD activity in both plants and CAT activity only in sunflower. The results showed that mycorrhizal inoculation by increasing biomass production and changing the activity of antioxidant enzymes increased the tolerance of both sunflower and safflower the tolerance of these plants against cadmium toxicity and improve the phytoextration in sunflower  in contaminated soils