Abstract: By the methods of nested PCR and DGGE, this paper studied the genetic diversity of arbuscular mycorrhizal fungi (AMF) under various vegetation types in Maolan Karst area, aimed to explore the AMF genetic diversity in Karst area. In the study area, the AMF genetic diversity index (3.50) and species abundance (41) were far higher than those (2.68 and 17, respectively) in non-Karst area. The high diversity of AMF in study area was closely related to the rich plant diversity and the special ecological environment, and was the result of long-term mutual choice of the AMF and Karst ecosystem. The AMF diversity under different vegetation types had significant difference, with the highest similarity index only 0.34. The community structure of the AMF changed significantly with vegetation type. Gene sequencing displayed that Glomus was the dominant genera, which had strong ecological adaptability and great potential in the ecological restoration of Karst rocky desertification.

Key words: Returning straw into soil, Soil organic matter, Soil fertility