中文摘要：

【目的】探明不同种类的植物对其根际土壤微生物数量分布与群落结构的影响。【方法】将微生物计数法与磷脂脂肪酸（PLFA）法相结合,分析比较麦积山景区3种典型裸子植物根际土壤微生物的数量分布和PLFA种类、含量及主成分结构。【结果】3种植物根际土壤微生物数量均以细菌最多,真菌最少;总PLFA含量以红豆杉[Taxus chinensis（Pilg）Rehder.]最高、种类最多,日本落叶松[Larix kaempferi（Lamb）Carriere.]最低,红豆杉与云杉（Picea asperata Mast）PLFA主要成分相似度高于日本落叶松;外来种日本落叶松无论微生物数量,还是种类以及PLFA结构组成与红豆杉、云杉均有较大的差异,多样性显著下降。【结论】与土著裸子植物相比,外来种日本落叶松能明显改变根际土壤微生物数量分布与群落结构。

英文摘要：

[Objective] In order to identify the microbial community structure of the different gymnosperm types. [Methods] Microbial culture and PLFA（Phospholipid fatty-acid analysis） methods were employed to study the microbe quantity, PLFAs types and content of three typical gymnosperms soil in scenic area of Maijishan, Gansu Province. [Results] There existed distinct difference on composition and structure of soil microbial. Microbial number was highest in bacteria and lowest in fungi. Total PLFAs content and types were the highest of Taxus chinensis（Pilg.） Rehder and lowest of Larix kaempferi（Lamb.） Carriere. Principal component of PLFA analysis that has high similarity with Taxus and Picea asperata Mast. than Larix kaempferi（Lamb.） Carriere. There was obvious difference with Microbial types and structure form of Larix kaempferi（Lamb.） Carrière. Diversity declined significantly than those in the others rhizosphere soils. [Conclusion] Microbial number and community structure in rhizosphere soil of Larix kaempferi（Lamb.） Carriere have significantly changed comparing with native gymnosperms.