Arbuscular Mycorrhizal Fungi Induced Changes of Pb Migration and Bacterial Community in Both the Rhizosphere and Non-rhizosphere Soils of Paspalum notatum

Arbuscular mycorrhizal fungi (AMF) can form symbiosis with many plants and the effect of AMF on phytoremediation of heavy metal has been a hot topic. But the effects of AMF on pollutants and microbes in rhizosphere and non-rhizosphere soil are still scarce. Therefore, the effects of AMF on plant growth, Pb translocation, and bacteria community in rhizosphere and non-rhizosphere soils spiked with Pb were investigated. It was found that AMF could significantly increase the uptake of Pb by Paspalum notatum, and Pb content was about 11 to 197 times higher in the root than that in the leaves. Besides, concentration of soil exchangeable Pb was significantly reduced after plant cultivation, and application of AMF increased the reduction (the exchangeable Pb concentrations of Pb300M and Pb3000M in the rhizosphere were 26.3% and 23.6% lower than that of Pb300 and Pb3000, respectively). The reduction was generally higher in the rhizosphere soil than that in the non-rhizosphere soil. The amount of Pb uptake by plants only accounted for a small part (4.9-21.7%) of the soil decreased exchangeable Pb, irrespective of AMF application, and most of the original exchangeable Pb was transformed into stabilized forms. Although bacteria community exhibited some differences between rhizosphere and non-rhizosphere soils, PCoA analysis indicated that both AMF and Pb were stronger impact factors affecting the beta-diversity of soil bacteria community than rhizosphere. The results of this study can help to clarify the impacts of AMF on phytoremediation of heavy metal.