Microbial communities in Pinus tabulaeformis mycorrhizosphere under different ecological conditions
不同生态条件下油松(Pinus tabulaeformis)菌根根际土壤微生物群落

BIOLOG Metabolic Fingerprinting was adopted to study microbial communities in Pinus tabulaeformis mycorrhizosphere under two different ecological conditions of Shangnan in South Shaanxi and Ansai in North Shaanxi. The results revealed that the microbes in P.tabulaeformis mycorrhizosphere were more liable to utilize such carbon sources as carbohydrates and amino acids in Ansai and Shangnan, and the number and activity of metabolic carbon sources for the microbes in P.tabulaeformis mycorrhizosphere were higher in Shangnan than in Ansai, and that the average well color development (AWCD) of microbes in the metabolism of same kinds of carbon sources in Shangnan sample was more than two times as much as that in Ansai. The dominant microbe species in P.tabulaeformis mycorrhizosphere in Ansai were the ones that metabolized amino acids. In contrast, the dominant microbe species in Shangnan sample were the ones that metabolized carbohydrates. The microbial community diversity indices and principal component analyses demonstrated that the significant difference between two samples mainly depended on carbohydrate-dominated carbon sources and secondarily on carboxylic acids and amino acids as the last. AWCD of microbial communities from Shangnan sample was significantly higher than that in Ansai (P<0.01). The quantity of the bacteria was significantly higher in Shangnan compared to in Ansai (P<0.05). The Shannon and the richness indices of the microbial community in samples from two places were significantly different (P<0.01). There was no significant difference observed between the infection rates but extremely significant difference between the ectomycorrhizal biomasses in the two samples (P<0.01). Correlation analysis showed that the ectomycorrhizal biomasses were positively related to the Shannon index (P<0.05), (AWCD) (P<0.01), and richness index (P<0.01). The activity, community size and diversity of microbes in P.tabulaeformis mycorrhizosphere were higher in warm, humid hilly regions of Shangnan than in Ansai, and the microbial communities in P.tabulaeformis mycorrhizosphere were more stable in dry region of the Loess Plateau in Ansai than in Shangnan.