Positive role of Mycorrhizal Fungi in the Alleviation of Zinc Toxicity in in Badami cultivar of pistachio (Pistacia vera L.) trees

On metal contaminated soils, ectomycorrhizal( ECM) fungi may improve plant growth through an enhanced nutrition or by alleviation toxicity of the metals. In order to evaluation of alleviating effects of ectomycorrhizal colonization on zn toxicity, a study was performed using pistachio plants and Agaricus bisporus fungus as factorial in a completely randomized design with three replications. The experiment included two factors: mycorrhizal (M) and non-mycorrhizal (NM) pistachio plants and five levels of the zn concentrations (0, 30, 60, 90 and 120 μm) in 3 replicates. In this study experiment was conducted to investigate the effect of ectomycorrhizal colonization in the alleviation of oxidative stress and improvements of the antioxidant enzyme activities, lipid peroxidation and metal accumulation in pistachio trees (Badami cultivar).The results showed that the increase of zinc concentration caused an increase in the malondialdehyde (MDA), and induction in antioxidative enzymes activity in the leaves of the M and NM plants, but it was dramatically more in M plants. A decrease of ascorbate (ASA) content was induced by increasing the zinc concentration where it was higher in M plants but all metal treatments increased dehydroascorbate (DHA) contents in both M and NM plants. The results showed that the Zn translocated from root to shoot in M plants was lower than NM plants. The amelioration of Zn toxicity by A.bisporus may be a result of improving the antioxidant defense system and prevent the absorption of heavy metals.