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以中草药麦冬为研究对象,采用变性梯度凝胶电泳(DGGE)方法,考察连作对麦冬根际土壤细菌群落的影响。结果表明,重茬麦冬根际细菌群落的Shannon-Wiener指数从苗期至快速生长期、再到块根膨大期分别为3.36-3.40-3.69,丰富度指数为55.0-61.5-63.5,均匀度指数为0.84-0.82-0.89;而同期正茬根际细菌群落的上述指数值分别为3.66-3.33-3.72、67.5-53.5-63.5和0.87-0.84-0.90。通过对土壤细菌群落的DGGE图谱进行主成分分析,结果显示,上述各个时期重茬与正茬样本均发生显著分离,表明连作改变了麦冬根际细菌群落的多样性变化趋势和结构组成。进一步比较麦冬块根膨大期根际主要功能菌群的数量变化,发现连作后氨化细菌和好气性纤维素分解菌数量增加,而硝化细菌和固氮菌的数量减少。对比发现重茬麦冬的产量仅为正茬的70.6%,表明麦冬连作减产与其根际土壤细菌群落的变化相关。
Taking Chinese herbal medicine Ophiopogon japonicus as research object, the influence of continuous cropping on bacterial community in rhizosphere soil of Ophiopogon japonicus was investigated by denaturing gradient gel electrophoresis (DGGE). The results showed that the Shannon-Wiener index of rhizospheric bacterial community after re-stubble intercropping was 3.36-3.40-3.69, and the abundance index was 55.0-61.5-63.5 from the seedling stage to the rapid growing stage. The evenness index 0.84-0.82-0.89, while the above index values of rhizospheric bacterial communities in the same period were 3.66-3.33-3.72, 67.5-53.5-63.5 and 0.87-0.84-0.90, respectively. Through the principal component analysis of DGGE map of soil bacterial community, the results showed that there was a significant separation of stubble and stubble in each period, which indicated that the change trend and structure of bacterial community in rhizosphere of stichopus japonicus were changed by continuous cropping. Furthermore, comparing the changes of the number of main functional microflora in rhizosphere of Ophiopogon japonicus, the number of ammonifying bacteria and aerobic cellulolytic bacteria increased, while the number of nitrifying bacteria and nitrogen-fixing bacteria decreased. The results showed that the yield of Ophiopogon japonicus was only 70.6% of the positive crop, indicating that Ophiopogon japonicus is related to the change of bacterial community in rhizosphere soil.