专用微生物肥对不同连作障碍土壤根际微生物区系的影响

摘要

In order to explore the effect of application of special microbial fertilizer on the rhizosphere microflora in different continuous cropping obstacles soil, the soils with different degrees of continuous cropping obstacles were collected and amended with 2% special microbial fertilizer to be used in the pot experiment for peppers cultivation. The methods of dilution plate count and PCR-DGGE were employed to analysis the rhizosphere microflora. The results obtained were as follows. With the increase of continuous cropping year, the number of rhizospheric bacteria and actinomycetes were decreased while the number of rhizospheric fungi was increased; After fertilization of special microbial fertilizer, the number of microbes had changed obviously, bacterial number increased 78.6%, 66. 7% , 54. 5% , fungi number decreased 5. 0% , 12. 5% , 7.5% , and actinomycetes number increased 18.2% , 9. 1% , 23. 5% in 3 different kinds of continuous cropping soils (with low, medium and high degrees of continuous cropping obstacles) , respectively; The PCR-DGGE fingerprinting showed that the richness and diversity index of rhizospheric microorganisms decreased with the increase of the rncontinuous cropping year while the population number and structure of rhizospheric microorganisms could be improved and the diversity index could be increased after fertilization of special microbial fertilizer. It was suggested that the special microbial fertilizer could have a significant effect on improving the population density and population structure of microorganisms in rhi-zosphere soil, but the improved effect could be different due to the different degrees of continuous cropping obstacles.%为探究专用微生物肥对不同连作障碍程度土壤根际微生物区系的影响,采用不同连作障碍程度的土壤为栽培介质,施用2％的专用微生物肥后进行辣椒土培盆栽试验,取根际土壤进行稀释平板计数和PCR-DGGE分析.结果表明:随着土壤连作障碍程度的增加,根际土壤细菌和放线菌数量减少,真菌数量增加；施用专用微生物肥后,土壤微生物种群密度发生显著性变化,其中土壤连作障碍程度轻、中、重组细菌数目分别增加了78.6％、66.7％、54.5％,真菌数目分别减少了5.0％、12.5％、7.5％,放线菌数目分别增加了18.2％、9.1％、23.5％.通过分析PCR-DGGE指纹图谱发现,随着生理性土壤连作障碍程度的加剧,根际土壤微生物的丰富度和多样性指数降低,施用专用微生物肥后,微生物种群数目和种群结构发生改变,多样性指数升高.说明专用微生物肥对根际土壤微生物种群密度和种群结构有显著性影响,但是由于土壤连作障碍程度的不同产生效果不同.