中文摘要：

外来生物入侵可能对生物群落结构和生态系统功能产生多种影响,但入侵植物与土壤微生物群落组成和多样性的关系尚不清楚。为了揭示外来植物紫茎泽兰（Eupatorium adenophorum）入侵对土壤化学性质和细菌群落组成及多样性的影响,本研究利用第二代高通量测序技术,比较了紫茎泽兰不同入侵程度的生境（本地植物群落、紫茎泽兰与本地植物混生群落、紫茎泽兰单优群落）土壤中细菌群落的差异。土壤化学性质分析表明,土壤p H值、有机质、全N和全K随着紫茎泽兰的入侵而逐渐降低,而土壤全P则在入侵程度最高的生境土壤中最高。通过测序共获得7,755个细菌OUT（operational taxonomic unit）。结果表明,紫茎泽兰入侵对土壤的细菌多样性影响较小,ACE和Chao指数在3种不同生境间的差异不显著。细菌在紫茎泽兰与本地植物混生群落中的Shannon指数最低,即细菌的多样性在中等入侵程度的生境最低。此外,紫茎泽兰入侵改变了土壤细菌组成和结构,酸杆菌门（Acidobacteria）和疣微菌门（Verrucomicrobia）的相对丰度,从本地植物群落、混合群落到紫茎泽兰单优群落,呈现出先增加后减少的趋势。可见,紫茎泽兰入侵一定程度上改变了土壤微生物的多样性和群落结构,并改变了土壤的化学性质。

英文摘要：

The invasion of alien species can affect biological community structure and ecosystem function- ing, but the relationships between invasive plants and soil microbial composition and diversity are still un- clear. In order to examine the effect of the invasion of an exotic plant Eupatorium adenophorum on soil chemical properties and microbial community structure and diversity, we compared the differences in soil microbial community of three communities with different densities of E. adenophorum （native plant commu- nity, E. adenophorum and native plant mixed community, and E. adenophorum dominated community） by high-throughput sequencing. Analysis of soil chemical properties showed that soil pH, organic matter, total nitrogen and total potassium decreased with increasing invasion of E. adenophorum. However, total phos- phorus was highest in the most heavily invaded soil. The high-throughput sequencing results showed that there were 7,755 soil microbial OTUs （operational taxonomic unit） in total. The invasion ofE. adenophorum did not exert heavy impacts on soil microbial diversity. ACE index and Chao index showed no significant differences among the three different communities. However, soil microbial diversity of the mixed commu- nity ofE. adenophorum and native plant species showed the lowest Shanonn index. The relative abundances of Acidobacteria and Verrucomicrobia in the medium invaded community were the highest. In sum, the inva- sion of E. adenophorum altered the diversity and structure of soil microbial communities, and changed the soil chemical properties.