Community diversity of bacteria and arbuscular mycorrhizal fungi in the rhizosphere of Amorpha fruticosa L., Hippophae rhamnoides L. and Robinia pseudoacacia L. in different ecological regions of Loess Plateau in Shaanxi Province of China

The research of rhizosphere microorganism community structure in degraded areas has been a focus recently. The aim of this study is to analyze the community diversity of bacteria and arbuscular mycorrhizal fungi (AMF) in the rhizosphere of Amorpha fruticosa L., Hippophae rhamnoides L. and Robinia pseudoacacia L. in three different ecological regions of Loess Plateau in Shaanxi Province of China by terminal restriction fragment length polymorphisms (T-RFLP). Results obtained that the AMF and bacterial diversity differed greatly between regions and native plants species. Species richness and the Shannon diversity index of bacteria and AMF in rhizosphere of R. pseudoacacia were higher than that of H. rhamnoides and A. fruticosa in the three regions. The results of principal component analysis and redundancy analysis (RDA) indicated that host plants had no strict specificity with both AMF and bacterial community diversity while environmental condition did great influence on AMF community diversity and organic matter content, and pH were primary influencing factor. The community diversity of AMF was significant correlative to that of bacteria (p<0.01). These results suggest that the environmental conditions exhibit greater influence on the community diversity of AMF than the host plants. And organic matter and pH are more indicative of the change of community diversity of bacteria and AMF.