杉木人工林土壤微生物群落结构特征

采用氯仿熏蒸法、稀释平板法和磷脂脂肪酸(phospholipid fatty acid,PLFA)方法,分析了常绿阔叶林转变成杉木人工林后土壤微生物种群数量和群落结构的变化特征.结果表明:常绿阔叶林转变为杉木人工林后,林地土壤的微生物生物量碳、可培养细菌和放线菌数降低.杉木人工林地总PLFAs、细菌PLFAs、真菌PLFAs比常绿阔叶林分别降低了49.4％、52.4％和46.6％,革兰氏阳性和阴性细菌PLFAs远低于常绿阔叶林.杉木人工林根际土壤微生物生物量碳、可培养细菌和放线菌数显著高于杉木人工林林地土壤,根际土壤中总PLFAs、细菌PLFAs、革兰氏阳性和阴性细菌PLFAs的含量也高于林地土壤,但真菌PLFAs和细菌PLFAs之比却低于林地土壤.对土壤微生物群落结构进行主成分分析发现,第1主成分和第2主成分共解释了土壤微生物群落结构变异的78.2％.表明常绿阔叶林与杉木人工林土壤的微生物群落结构间存在差异.

Characteristics of soil microbial community structure in Cunninghamia lanceolata plantation

By using dilution plate,fumigation extraction,and phospholipid fatty acid(PLFA) methods,this paper studied the quantities of soil microbial populations and the characteristics of soil microbial community structure in a Chinese fir(Cunninghamia lanceolata) plantation converted from an evergreen broadleaved forest.The results showed that,during the vegetation change from evergreen broadleaved forest to Chinese fir plantation,the microbial biomass carbon and the quantities of culturable bacteria and actinomyces were decreased.The total PLFAs,bacterial PLFAs,and fungi PLFAs in the woodland soil from Chinese fir plantation were decreased by 49.4%,52.4%,46.6%,simultaneously.And G+ and G-bacterial PLFAs in Chinese fir plantation were lower than in evergreen broadleaved forest.As compared with those in rhizosphere soil from Chinese fir plantation,the microbial biomass carbon and the quantities of culturable bacteria and actinomyces in bulk soil were decreased.The total PLFAs,bacterial PLFAs,and G+ and G-bacterial PLFAs in the rhizosphere soil were increased,while the ratio of fungal to bacterial PLFAs was lowered.The principal component analysis of the soil microbial community structure indicated that the first principal component(PC1) and the second principal component(PC2) together accounted for 78.2% of total variation of soil microbial community structure.This study showed there were some differences in the soil microbial community structure between evergreen broadleaved forest and Chinese fir plantation.