轮作与连作对烤烟不同生育期根际土壤细菌群落结构的影响

为明晰烤烟连作是否对根际细菌群落结构产生影响,采集不同生育时期的轮作和连作烤烟根际土壤,运用 454焦磷酸测序技术,对根际土壤细菌 16S rDNA V1-V3片段序列结构组成进行分析。结果表明,与轮作处理相比,连作处理烤烟根际酸杆菌门丰度在生育前期低而在后期高,但 α-变形菌门和放线菌门表现出相反的变化趋势;烤烟连作降低了表征菌群丰度的 Chao指数和物种丰富度的 Shannon指数,表明烤烟连作降低了根际土壤细菌多样性。主成分分析和 NMDS(non-metric multidimensionalscaling)的聚类分析结果显示不同处理烤烟根际细菌群落结构随生育期而迁移,轮作与连作烤烟根际土壤细菌群落结构差异在生育前期体现明显,生育后期不明显,表明生育期是影响烤烟根际细菌群落结构变化的主要因素,而连作与轮作是次要因素。 

Effects of rotational and continuous cropping on bacterial community structures in rhizospheric soil at different growth stages of flue-cured tobacco

In order to study effects of continuous cropping of flue-cured tobacco on rhizosphere bacterial community structures. Rhizosphere soils of rotation and continuous cropping of tobacco at different growth stages were collected. V1-V3 partial sequences of bacterial 16S rDNA were analyzed by 454 pyrosequencing method. Results showed that, compared with rotation treatments, the relative abundance of Acidobacteria was higher in earlier growth stages and lower in later stages in continuous cropping of flue-cured tobacco, while the relative abundances of α-proteobacteria and Actinobacteria showed the opposite. The community richness(Chao) and diversity(Shannon) in continuous cropping were lower than those in rotation, suggesting that continuous cropping reduced bacterial community diversity. Principal component analysis and cluster analysis based on non-metric multidimensional scaling showed that bacterial communities changed with tobacco growth stages, and difference of community between continuous cropping and rotation was detected in earlier growth stages, not in later stages, suggesting that growth stage was the primary factor and continuous cropping or rotation was the second factor in determining tobacco rhizosphere bacterial community.