不同施肥处理对太湖地区水稻土团聚体粒组细菌和真菌组成和多样性的影响

选择太湖地区水稻-油菜轮作的长期肥料试验的水稻田，采集原状土进行团聚体颗粒分离，提取土壤微生物DNA进行PCR-DGGE分析，通过对DGGE结果进行主成分分析和多样性指数的计算，比较秸秆还田和化肥配施与单施化肥两施肥处理对土壤团聚体中微生物群落组成和多样性的影响。结果表明：与单施化肥相比，秸秆还田显著改变了2 000 ~ 200 μm和200 ~ 20 μm两粒组中细菌和真菌的群落组成，说明较大颗粒组中微生物群落组成灵敏响应施肥措施的变化。不同团聚体粒组微生物群落多样性存在差异，细菌的多样性在2 000 ~ 200 μm与＜2 μm粒组中较高，真菌则在大粒组中表现出较高的多样性，而且由团聚体粒组本身带来的微生物多样性的变异大于施肥措施引起的变异。

Influences of long-term fertilization on bacteria and fungi community structures in different aggregate-size aggregates of paddy soil in Taihu Lake region of China

Taking a long-term fertilized paddy soil in Taihu Lake region as research object and continuously rice-rape rotation has been conducted.The microbial community structures and diversity in < 2,2-20,20-200,and 200-2 000μm aggregates under no fertilization(NF),chemical fertilization(CF),chemical fertilization plus straw return(CFS) were investigated through by PCR-DGGE analyze.The results showed that fertilization,chemical fertilization plus straw return,affected the bacteria and fungi community structures in 2 000-200μm and 200-20μm aggregates more than chemical fertilization only,which suggested the high sensitivity of microbial community structure changes in the larger aggregates.There were significant difference of microbial community structure diversity in different aggregates,the diversities in 2 000-200μm and<2μm aggregates were higher for bacteria and higher in larger aggregates for fungi.The variance caused by different aggregates was more than different fertilization.