施用韩国假单胞菌(Pseudomonas koreensis)CLP-7对连作烟田土壤质量及微生物群落功能多样性的影响

针对目前连作导至植烟土壤酸化和根茎病害发生重的问题,田间条件下,研究了嗜酸性韩国假单胞Pseudomonas koreensis CLP-7对酸化植烟土壤pH、养分、酶活性及微生物群落功能多样性的影响。结果表明:CLP-7可以提高酸化植烟土壤pH;同时,CLP-7显著提高根际土壤速效钾、有效磷、铵态氮、硝态氮和有机质含量,其中有机质含量增加最显著;根际土壤脲酶、蔗糖酶活性呈上升趋势且均高于未施菌土壤,过氧化氢酶活性变化不明显。CLP-7处理不同时间的土壤微生物代谢多样性指数表现出明显的差异,施菌30 d时Shannon指数、Simpson指数,Richness及McIntosh指数均达到最高;所有处理的Pielou指数变化较小。微生物碳代谢主成分分析结果显示,施菌30 d时,根际土壤微生物对碳源利用与其他处理差异显著,主要为羧酸类和糖类碳源;随着施菌时间增加,微生物对氨基酸类、羧酸类、双亲化合物类、聚合物类和糖类利用率明显提高,说明CLP-7有利于提高连作烟田根际土壤微生物对碳源的利用能力。综上所述,P.koreensis CLP-7能够明显提高土壤pH、土壤酶活性,增加土壤养分含量和土壤微生物群落功能多样性,进而改善酸化植烟土壤质量,在微生物修复酸化土壤和减轻根茎病害发生的烟草绿色防控中具有较大的应用潜力。

Effects of adding Pseudomonas koreensis CLP-7 on soil quality and soil microbial community functional diversity in continuous cropping tobacco fields

Aiming to the soil acidification and serious root disease of tobacco caused by continuous cropping, this study investigated the roles of Pseudomonas koreensis CLP-7 in soil pH, nutrients, enzyme activity and soil microbial community diversity of acidified rhizosphere soil of tobacco. The experiments were carried out in the field. The effects of pH, content of nutrients, soil enzyme activity were determined by chemical methods. The study of soil microbial community diversity was conducted with BIOLOG micro plate. The results showed that acidophilic P. koreensis CLP-7 significantly improved pH, the content of available K, available P, NH₄⁺-N, and NO₃^--N. The organic matter of acidified rhizosphere soil were higher than that of CK. The increase of organic matter content was the most significant. The urease and invertase activities of rhizosphere soil after adding CLP-7 were significantly higher than those in the untreated soil, but the catalase activity was not obvious. In 30 d of CLP-7 application, with the increasing time of CLP-7 application, the microbial diversity index of rhizosphere soil of tobacco showed obvious difference. At the 30th day of adding CLP-7, Shannon index, Simpson index, Richness and McIntosh index were reached the highest level, but the Pielou index changed a little. The results of principal component analysis of microbial carbon source metabolism showed that the soil microbes had significant differences in carbon source utilization after CLP-7 application, especially carboxylic acids and carbohydrates carbons. As the application time increased, the microbial utilization ratios of amino acids, carboxylic acids, miscellaneous, polymers and carbohydrates were significantly improved. It was indicated that CLP-7 was beneficial to improve the utilization of carbon sources in rhizosphere soil microorganisms in continuous cropping fields. This study showed that the application of acidophilic P. koreensis CLP-7 could improve the quality and microbial functional community diversity of acidified tobacco soil and create a soil ecological environment that was favor of tobacco growth, which had a greater potential to application in microbial bioremediation and tobacco green control.