Influence of arbuscular mycorrhizal fungi and an improving growth bacterium on Cd uptake and maize growth in Cd-polluted soils

In a pot experiment, the effects of the bacterium strain Micrococcus roseus, native soil arbuscular mycorrhizal fungi (AMF) and the fungus Glomus mosseae on the growth, P, N, Fe, Mn, Zn and Cd uptake of maize in a soil polluted with Cd were investigated. A three-factor experiment was set up in a randomized complete design with three replicates of each treatment. The factors in the experiment were as follows: 1) AMF with two levels, G(1) (native AMF) and G(2) (G. mosseae, G(1)); 2) bacterium promoting plant growth with two levels, B-0 (no inoculation) and B-1 (inoculation with M. roseus); and 3) cadmium with three levels (0, 100 and 200 mg Cd kg(-1) soil). G(2) significantly increased root colonization, plant biomass, shoot nutrients and Cd uptake of plants in comparison with G(1) in Cd polluted conditions. The single presence of AMF contributed to the stabilization of Cd in roots and soil. Shoot and root dry weights, and shoot nutrients uptake of plants co-inoculated with bacterium and AMF were higher than mycorrhizal plants in the soil polluted with Cd. Plants co-inoculated with bacterium and G(2) had higher amount of shoot Cd uptake, root Cd uptake, Cd phytoextraction, translocation, and uptake efficiencies under both Cd concentrations than only mycorrhizal plants. The results showed that, most of the Cd was sequestered in roots of plants co-inoculated with bacterium and native AMF in the soil with 100 and 200 mg Cd kg(-1).