【作者】 罗红燕； 蒋先军； 谢德体；

【Author】 LUO Hongyan,JIANG Xianjun,XIE Deti (College of Resource and Environment,Southwest University,Chongqing 400715)

【机构】 西南大学资源环境学院；

【摘要】 本文首次报道亚热带紫色水稻土中土壤细菌在不同粒径水稳性团聚体中的遗传多样性分布及耕作的响应。实验样品采自16年的国家紫色土长期定位试验站的垄作免耕(CombiningRidge and No-tillage,RNT)、冬水稻田(Flooded Paddy Field,FPF)和常规平作(ConventionalTillage,CT)土壤。表层土样(0～20cm)通过湿筛法分别得到>4.76mm、2.0～4.76 mm、1.0～2.0mm、0.25～1.0mm、0.053～0.25mm、<0.053mm粒径的土壤团聚体。采用PCR-DGGE测定细菌的遗传多样性分布。结果显示:从三种不同耕作方式的图谱中能分离得到30～43条带,说明土壤水稳定性团聚体中的微生物种类非常丰富。从图谱条带数目和强度中可以看出,在三种不同耕作方式中,各团聚体粒径分布的优势细菌类群的强度非常明显,可以较好地比较出不同耕作方式下的不同团聚体粒径中的优势细菌类群。各耕作方式图谱条带的Shannon指数均不一致,表明在各耕作方式下的团聚体粒径中的物种富度有差异,但总体显示出一定的规律,即在>4.76和<0.25mm的粒径中,多样性指数普遍显示大于在0.25～4.76之间的粒径,在三种耕作方式中,DGGE图谱条带相似性Cs值差异很大,从26.3到82.1,说明团聚体粒径大小不同,其中的细菌种类的分布也有较大差异。从聚类分析中可得出,耕作方式和团聚体粒径大小的不同,都会影响细菌同源性的分布。PCR-DGGE技术对成分复杂的各耕作方式下各团聚体粒径样品中细菌种群结构的动态变化和分析是可行的。更多还原

【Abstract】 The distribution patterns of bacteria in different water-stable aggregates(WSA),and the effects of tillage methods on bacterial genetic diversity,were investigated in a long-term field experiment.Tillage treatments examined in this study included Conventional Tillage(CT),Flooded Paddy Field(FPF),Combining Ridge and No-tillage(RNT).A wet sieving method was used to separate soil aggregates into six groups based on particle diameter:>4.76 mm,2.0～4.76 mm, 1.0～2.0 mm,0.25～1.0 mm,0.053～0.25 mm and<0.053 mm.Bacterial biomass were estimated by PCR-DGGE,respectively,in the samples.From three different farming in the map can be obtained about 30～43 band,explain the reunion of soil water stability is very rich in bacteria.From the map channel number and strength,which can be seen in three different ways of cultivation,the reunion of the particle size distribution body advantage bacterium group’s strengthen,can compare different ways of farming in different particle size advantage bacterium body of reunion.Each of the map channel farming Shannon index,in every way that the reunion of body under cultivation species richness of the particle size,but overall shows certain laws,namely in>4.76mm and<0.25 mm particle size,diversity index generally display than 0.25～4.76 mm,in between the three types of farming,DGGE map channel similarity Cs value difference,from 26.3 to 82.1 reunite body size, different types of bacteria,which also has a bigger difference of distribution.From the cluster analysis can draw,farming and reunite the different particle size body all affect the distribution of bacteria.PCR-DGGE technology of complicated composition farming the bacteria in the body size samples reunites the dynamic changes of population structure and analysis is feasible.The results of this study indicate that bacterial genetic diversity in the soil is related to the particle size of the soil aggregates as well as to the tillage method.The Combining Ridge and No-tillage(NT) treatment yielded the highest bacterial genetic diversity associated with WSA,which suggests soil health is maximized when soil disturbance is kept to a minimum.更多还原