不同栽培环境下有机与常规蔬菜土壤的细菌群落多样性差异

土壤细菌群落在蔬菜栽培中发挥着重要作用。基于DNA和RNA水平,利用PCR-DGGE技术研究了不同栽培环境下有机与常规蔬菜土壤细菌群落多样性差异,以及土壤理化性质与细菌群落多样性的关系。结果表明：不同栽培方式下土壤细菌多样性存在明显差异,土壤微生物的优势种群和数量受有机、常规栽培和季节影响,有机栽培较之常规栽培能够显著增加土壤细菌群落多样性;聚类分析表明,16S rDNA细菌群落多样性与季节相关,而16S rRNA细菌群落多样性与栽培方式相关;差异条带测序显示,大多细菌与不可培养细菌种属有较高同源性,其余9种推测属于假单胞菌属;CCA分析说明pH是影响土壤细菌群落多样性的主要因素,有机栽培土壤中微生物生物量C、N以及有机质含量显著高于常规栽培土壤。综上,有机栽培能够丰富活性细菌群落多样性,具有土壤优化效应。

Bacterial Community Diversity of Vegetable Soils in Organic and Conventional Managements Under Different Cultivated Environments

Bacterial community plays a significant role in vegetable cultivation.In this study,PCR-DGGE method was used to study patterns of bacterial community diversity under organic versus conventional management in horticultural soil based on 16S rDNA/rRNA.Also its relationship with soil physicochemical properties was researched.The results indicated that soil bacterial diversity has a significant change under different managements and sample period as analysis DGGE gels.Moreover,the abundance of each dominant band varied among each treatment during sample period.On the other hand,by observing 16S rRNA DGGE fingerprint we found that there is less variability than 16S rDNA fingerprint has,and 16S rRNA DGGE fingerprint can be grouped separately in terms of organic and conventional management by UPGMA.Additionally,analysis of 16S rDNA DGGE fingerprint indicated a seasonal influence on bacterial community.From 26 different bands which were excised from DGGE gel,the result showed us that there were 9 bands belong to Pseudomonas and the rest of bands belong to uncultured bacterium clones.Shannon-Wiener index showed organic management promoted bacterial diversity of soil more intensively than conventional management does.According to the figure drew by CCA,it points out soil pH is the strongest environmental factor which can influence soil bacterial diversity.Meantime,the level of microbial mass C,N and organic matter had a significant increase under organic management.On the other side,it indicated that soil of greenhouse had a higher humidity than soil from open field.During the same period,pH value was higher in organic management soil than it under conventional management virtually.In sum,organic management can diversify active bacterial community and have beneficial ecological effects.