Effect of Arbuscular Mycorrhizal Fungi on Lead Phytoremediation by Sorghum (Sorghum bicolor L.)

Arbuscular mycorrhizal fungi in association with plant roots may affect plant growth, nutrition and tolerance to heavy metals in polluted soils. Therefore, this association can play an important role in phytoremediation. In this study, the effects of two arbuscular mycorrhizal fungi species including Glomus intraradices and Glomus mosseae, on the uptake and translocation of Pb in sorghum, were investigated under greenhouse conditions. The experiment was conducted as factorial, completely randomized design including four levels of Pb2+ (0, 200, 400 and 600 mg Pb2+ kg-1) and three treatments of fungi (two mycorrhizal fungi species and a non-mycorrhizal plant) with four replications. Lead were added to the pots as Pb(NO3)2. The Results indicated that symbiosis with G. intraradices increased shoot dry weight at 200 and root dry weight at 400 and 600 mg Pb kg-1 compared to the non-mycorrhizal treatment. There were, however, no significant effects on other growth parameters. Both mycorrhizal fungi caused a significant decrease in Pb2+ translocation from the root to the shoot. However, the shoot and root dry weights, leaf area and chlorophyll content in plants inoculated with G. mosseae at higher levels of Pb2+ were considerably (p<0.05) decreased compared to the non-mycorrhizal plants. At pb levels of 400 and 600 mgkg-1, the ratio of Pb concentration in root to that of shoot in plants inoculated with G. mosseae was significantly (p<0.05) greater than that of plants inoculated with G. intraradices and none inoculated ones.