盐碱胁迫对巨菌草根际土壤微生物多样性及酶活性的影响

Salinty and alkali are the serious stress in arid and semiarid area, which has a bad effect on plant growth. It is necessary for us to explore the variety of microbial community and the activity of enzyme in rhizosphere of Pennisetum giganteum(giant juncao) under saline-alkali environment. As a result, we set up seven kinds of saline and alkaline concentration experiment, with the method of SPSS to analyze the difference significance and correlation of physiological data under different saline and alkaline concentration. We analyzed the diversity of microbial communities with the method of Illumina high-throughput sequencing. The results were as follows: The composition of microbial communities in inter-root soil of giant juncao differed at different saline-alkali stress. The dominant groups were Sordariomycetes (68.5%), Eurotiomycetes (16.3%), Chloroflexia (8.5%), Bacteroidia (13.5%), Gemmatimonadetes (5.6%) and - Proteobacteria (3.7%) at the 12 saline concentration; The relative abundance of the Dothideomycetes (27.7%)and Anaerolineae (2.4%) was sharply reduced to 2.5% and 0.007% when the saline-alkali concentration increase from 6 to 12; The Chao and Shannon indices of the inter-root microbial community of giant juncao decreased with increasing saline-alkali concentration, and were significantly correlated with soil salinity (P<0.01). The low concentration of saline-alkali stress had a positive effect on activities of urease, polyphenol oxidase and alkaline phosphatase in rhizophere soil of giant juncao, but activities of polyphenol oxidase, alkaline phosphatase and sucrase were inhibited when the saline-alkali content of soil exceeded 8. After planting giant juncao, the content of soil organic matter increased significantly (P<0.05) and the saline-alkali content would be reduced to a certain extent (P<0.05).The neutralizing ability to soil alkalinity gradually weakened with the increase of the saline-alkali concentration, and the neutralizing ability of soil salinity gradually weakened when the concentration exceeded to 8. When the saline-alkali concentration is 6, the production of giant juncao is the highest and the soil has a higher content of available nutrients and organic matter.The research showed that, growing giant juncao is beneficial to improving the fertility of saline-alkali soil by adjusting the enzyme content to better adapt to the medium and low concentration saline-alkali soil environment, and producing the corresponding dominant flora to adapt to the environment in different degrees of saline-alkali soil.