化肥对稻田土壤细菌多样性及硝化、反硝化功能菌组成的影响

以中国科学院桃源农业生态试验站长期定位施肥试验为平台,采用聚合酶链式反应(polymerase chain reaction,PCR)和DNA序列测定技术分析研究了3种长期施肥制度(对照不施肥-CK,单施氮肥-N,氮磷钾肥-NPK)对土壤细菌群落以及硝化、反硝化微生物种群的影响.通过系统分析细菌16S rDNA、细菌的硝化基因氨单加氧酶(ammonia monooxygenase,amoA)和反硝化基因氧化亚氮还原酶(nitrous oxide reductase,nosZ)等基因文库发现,长期单施氮肥导致细菌16S rDNA和amoA的多样性明显低于CK和NPK处理,而nosZ的多样性与之相反,即单施氮肥处理明显高于CK和NPK处理.LUBSHUFF软件统计分析显示:16S rDNA和amoA基因文库在CK与N,CK与NPK,NPK与N处理间均存在显著性差异.而对于nosZ基因文库,N和NPK与CK处理相比呈现出了显著性差异,N与NPK之间的差异没有达到显著水平.上述结果表明长期施用化肥对水稻土细菌的群落结构及硝化和反硝化细菌组成产生了明显的影响,但这种影响因基因类型而异.

Effect of fertilization on bacterial community, genetic diversity of amoA and nosZ genes in paddy soil

Polymerase Chain Reaction (PCR) and DNA sequencing techniques were applied to explore the effects of long-term fertilization on the community of bacteria and diversity of nitrifying and denitrifying bacteria in paddy soil. The analyses were based on the sequence libraries of 16S rDNA, amoA and nosZ genes. The Shannon Indices indicated that the diversity of soil bacteria and amoA gene of N treatment was lower than that of CK and NPK treatments, whereas the diversity of nosZ gene was opposite while the highest diversity occurred in N treatment. The LUBSHUFF statistical analyses demonstrated that both bacterial 16S rDNA and amoA gene libraries of CK, N and NPK treatments were significantly different from each other. As to the nosZ gene libraries, N and NPK treatments were remarkably different from CK, however, no significant difference was found between N and NPK treatments. It inferred that the application of chemical fertilizers influenced the community structure of bacteria and the functional genes of amoA and nosZ.