Effects of climatic and edaphic factors on arbuscular mycorrhizal fungi in the rhizosphere of Hippophae rhamnoides in the Loess Plateau, China

In order to investigate the effects of climatic and edaphic factors on arbuscular mycorrhizal (AM) fungi in the rhizosphere of Hippophae rhamnoides in the Loess Plateau, spore density, mycorrhizal colonization and gene diversity were analyzed by using the methods of microscopy and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) respectively. The results showed that H. rhamnoides could form strong symbiotic relationships with AM fungi. There existed obvious differences in AM fungal colonization among five sampling sites in the Loess Plateau (P<0.05). Correlation analysis showed that AM fungal colonization and spore density were closely related with climatic and edaphic factors. 42 different species (band types) were found in the DGGE gel. Based on analysing the position and intensity of AM fungal DGGE bands, the gene diversity indices, including species richness, evenness, Simpsom’s and Shannon-Weiner index, showed significant differences among five sampling sites (P<0.05). All the AM species could be classified into four groups in the biplot of canonical correspondence analysis (CCA), and each group had various responses to climatic and edaphic factors. Monte Carlo random test indicated that soil available phosphorus (F=2.26, P=0.025) and spore density (F=1.76, P=0.006) were the dominating factors affecting AM fungal communities. In conclusion, AM fungal colonization and community diversity in the rhizosphere of H. rhamnoides showed obvious spatial heterogeneity among the different areas of the Loess Plateau, and climatic and edaphic conditions were important factors affecting the AM fungal communities. Therefore, screening and application of AM fungal strains in the Loess Plateau need to fully consider the local climatic and edaphic conditions.