连作对烟草根际土壤细菌碳代谢指纹的影响

Effect of continuous cropping on carbon metabolic fingerprint of tobacco rhizosphere soil bacteria

为了探究连作对烟草根系微生态的影响,采用Biolog技术分析了不同连作年限下烟草根际土壤细菌的碳代谢指纹差异。结果表明:根际土壤细菌对31种碳源的AWCD值随连作年限的增加而下降,与CK相比,连作5,10年后分别下降12.7%,74.0%;但6类不同碳源之间AWCD值降幅差异较大,连作5,10年后,降幅分别为3.7%~52.1%,64.9%~80.3%;主成分分析表明,以糖类、氨基酸类碳源利用为主的细菌数量显著减少是导致碳源总体利用能力下降的主要因素;连作改变了烟草根际细菌的代谢特征,表现为对糖类、氨基酸类碳源利用率下降,对多聚物类碳源利用率增加;连作降低了根际土壤细菌的香浓指数(丰富度)。

The Biolog technology was adopted to study the effect of different continuous cropping years on rhizosphere bacteria of tobacco.The results showed that：The average well color development（AWCD）of 31 kinds of carbon sources of rhizosphere soil bacteria decreased with the rise of continuous cropping years,and it decreased by 12.7%and 74.0%respectively after 5 and 10 continuous cropping years.The difference of AWCDchanges of the 6 types carbon sources was obvious,for the decrease was 3.7%~52.1%,64.9%~80.3% respectively after 5 and 10 continuous cropping years compared with that of CK.Principal component analysis showed that the decline of bacteria for which utilized carbohydrates and amino acids was the main factor reducing metabolic activity.Continuous cropping changed the metabolic characteristics of rhizosphere soil bacteria,for that the utilization rate of carbohydrates and amino acids decreased,while the utilization rate of polymers increased.The shannon index of rhizosphere soil bacteria was declined by continuous cropping.