不同种植年限香榧根际土壤微生物多样性

为探明不同种植年限对香榧根际土壤微生物群落特征的影响,采用高通量测序技术,分析种植5 a、10 a和15 a香榧根际土壤细菌、真菌的群落结构和多样性特征.结果表明: 在种植15 a的香榧土壤中细菌Chao1指数、ACE指数和Shannon指数显著降低,Simpson指数无显著变化.NMDS分析显示,种植年限对细菌群落结构变化有显著影响,而种植5 a和10 a香榧林地土壤具有相似的细菌群落.细菌相对丰度、多样性以及群落结构(基本上由变形菌、放线菌、酸杆菌和绿弯菌组成)的变化与有机质、C/N、全氮呈极显著相关.香榧根际土壤真菌Chao1指数和ACE指数随种植年限的增加显著降低,Shannon指数和Simpson指数在种植10 a香榧林地中较高.真菌NMDS分析显示,相同种植年限土壤真菌群落聚在一起,不同种植年限之间能明显分开.真菌优势菌群主要包括子囊菌门、担子菌门、接合菌门.有机质是影响真菌丰富度、多样性和群落结构变化的主要因子.综上,香榧根际土壤微生物群落随种植年限不同而发生明显变化,种植年限、C/N、土壤全氮和有机质含量是影响香榧根际土壤微生物群落结构的主要因子.

Microbial biodiversity in rhizospheric soil of Torreya grandis ‘Merrillii’ relative to cultivation history

To examine the effects of different cultivation history (5 a,10 a, and 15 a) on soil microbial communities, we used Illumina sequencing to investigate the diversity and structure of soil bacterial and fungal communities from Torreya grandis ‘Merrillii’ fields. The results showed that bacterial Shannon index, the richness estimators Chao1 and ACE were lower in soil in 15 year-old stand than those in other cultivation histories, while Simpson index showed no significant variation. Results from bacterial community NMDS showed that cultivation history played a vital role in driving the changes of soil bacteria communitiy structure. The bacterial communities in 5 and 10 year-old stand had the similar composition. The variations of bacterial richness and diversity as well as community structure (comprised basically of Proteobacteria, Actinobacteria, Acidobacteria, and Chloroflexi) were significantly correlated with soil organic matters, soil C/N, and total nitrogen. The fungi richness estimators of Chao1 and ACE were significantly decreased with increasing cultivation history. Shannon and Simpson indices were significantly higher in soil with 10 year-old stand than soils with other cultivation history. Fungal NMDS could be clustered in the same era. Fungal communities were comprosed of Ascomycota, Basidiomycota and Zygomycota. Changes in fungal richness/diversity and community structure were mainly controlled by the variation of soil organic matter. In conclusion, the predominant factors affecting soil microbial communities were the cultivation history, soil C/N, total nitrogen and organic matter, respectively.