枯草芽孢杆菌Bs-15对板栗土壤微生物种群数量及功能多样性的影响

Influence of Bacillus subtilis Bs-15 on the microbial population and functional diversity of microbial communities in the chestnut soil

土壤微生物是维持土壤质量的重要组成部分,是土壤中生物活性的具体体现。土壤微生物多样性的变异可反映其对环境的响应与适应,能敏感反映生态系统的功能演变和生态环境的变化。本研究采用固体平板法研究了枯草芽孢杆菌(Bacillus subtilis)Bs-15对板栗(Castanea mollissima BL)土壤微生物种群数量的影响,并通过BIOLOG ECO微孔板法分析Bs-15对板栗土壤功能多样性的影响。结果表明,接种Bs-15后,土壤中细菌数量比对照略有增加,但差异不显著;接种后放线菌的数量与对照相比有所减少,第7天达到极显著(p<0.01)差异,之后差异变小,第14 d开始,处理与对照之间放线菌数量基本持平;真菌数量则先增加后减少,第7天开始接种后的真菌数量与对照相比达极显著(p<0.01)差异。BIOLOG ECO微孔板分析显示,Bs-15使得土壤中微生物的AWCD值变大,72小时以后,AWCD值与对照相比差异达到极显著(p<0.01)水平;接种Bs-15后增大了土壤微生物多样性指数,其中Shannon多样性指数、Simpson多样性指数和McIntosh多样性指数分别增加了4.09%、6.01%和7.20%,对对照相比差异均达到极显著水平(p<0.01),Simpson均匀度和McIntosh均匀度分别增加了2.07%和2.53%,与对照相比差异均达到显著水平(p<0.05)。本研究结果表明,Bs-15不但提高了板栗土壤微生物的整体活性,丰富了土壤微生物种群,有利于保持和促进土壤肥力和健康状况;还提高了板栗土壤微生物功能多样性,使板栗土壤微生态系统功能更加稳定。

Soil microbial communities and its functional biodiversity are important ecologically-relevant information about the soil biological quality and fertility, and the variation of biodiversity would reflect its response and adaptation to the environment, and reflect the functional evolution of ecosystem and changes of ecological environment. In this research, we investigate the potential effects of Bs-15 on the microbial community and its functional diversity of soil microbes from chestnut plants via solid plate method and BIOLOG ECO microplate assay respectively. The results showed that after Bs-15 inoculation, the number of bacteria in soil increased without significant difference, and the number of actinomycetes decreased a little at first, with significant difference at p〈0.01 level in 7 d, after that the number of actinomycetes increased, and recovered to the control lever since 14 d. While the number of fungi increase first and then decreased, with significant difference atp〈0.01 level since 7 d. The BIOLOG ECO plates analysis showed that average well color development （AWCD） value of the microbial communities in the Bs-15-inoculated soil increased a little before 72 h, and significantly （p〈0.01） after 72 h. In the presence Bs-15, the parameters （Shannon index, Simpson index and McIntosh index） of the functional diversity of the soil microbial communities increased 4.09%, 6.01% and 7.20% respectively, with significant difference atp〈0.01 level, and Shannon uniformity and McIntosh uniformity increased 2.07% and 2.53% respectively, with significant difference atp〈0.05 level, which well reflected positive changes in utilization capacity of Bs-15 and the soil microbial communities, and indicated that Bs-15 may trigger an increase in total microbial activity of chestnut soil, increase of soil fertility, enrichment of soil communities and stabilization of soil ecosystem.