不同生态条件下油松(Pinus tabulaeformis)菌根根际土壤微生物群落

利用BIOLOG代谢指纹方法分析了陕南商南和陕北安塞不同生态条件下油松菌根根际土壤微生物群落。结果表明，安塞油松和商南油松菌根根际微生物对糖类和氨基酸类碳源较易利用，商南油松菌根根际微生物总体上代谢碳源的种类和活性远大于安塞油松，而且对同类碳源的代谢商南油松的AWCD比安塞油松均高出2倍多。安塞油松菌根根际微生物以氨基酸类代谢群为优势类群，商南油松以糖类代谢群为优势类群。微生物群落多样性指数和微生物群落主成分分析（PCA）指标均表明商南油松和安塞油松菌根根际土壤微生物群落有明显不同，起分异作用的碳源主要为糖类，其次是羧酸类和氨基酸类。商南油松菌根根际土壤微生物群落AWCD极显著高于安塞油松（P〈0．01），细菌数量显著高于安塞油松（P〈0．05），Shannon指数和丰富度指数达极显著性差异（P〈0．01），商南油松和安塞油松菌根侵染率差异不显著，但菌根生物量差异达极显著水平（P〈0．01）。相关性分析表明，菌根生物量与丰富度指数、AWCD呈极显著正相关，与Shannon指数呈显著正相关，但是与菌根侵染率相关性不显著。在商南温暖潮湿丘陵区油松菌根根际微生物活性、群落大小和多样性高于安塞油松，在安塞黄土高原干旱区微生物群落稳定性强于商南油松。

Microbial communities in Pinus tabulaeformis mycorrhizosphere under different ecological conditions

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.