Comparisons on microbial community structure and part of physicochemical indexes in soil of invasive zone of Rhynchelytrum repens with different degrees and their correlation analysis.
Difference in microbial community structure in soil of non-, mild- and severe-invasive zones of Rhynchelytrum repens (Willd.) C. E. Hubb. was compared by phospholipid fatty acids (PLFAs) analysis method, and difference in part of physicochemical indexes in soil of invasive zone with different degree was compared. On the basis, correlations of content of different types of microbes in soil with part of physicochemical indexes were analyzed. The results show that there are 37 species of microbes in soil of invasive zone with different degrees, which include 28 species of bacteria, 4 species of actinomyces, 4 species of fungi and 1 species of protozoan, in which, content of bacterium is the highest. PLFAs content of 6 species of microbes is high, and they distribute in all of three invasive zones; that of 27 species of microbes is low, and they also distribute in all of three invasive zones; and PLFAs content of 4 species of microbes is low, and they distribute in individual invasive zones. With aggravation of invasive degree of R. repens, contents of bacterium, fungus and protozoan in soil all increase gradually, and their content in soil of severe-invasive zone is higher by 11.34%, 19.60% and 13.95% than that in non-invasive zone with a value of, respectively. And species of microbes in soil also increases gradually. With aggravation of invasive degree of R. repens, activity of catalase in soil decreases gradually, activities of sucrase and urease, pH value and water content of soil all increase gradually, while change in activity of cellulase of soil is small. Compared with non-invasive zone, activity of catalase in soil of severe-invasive zone decreases by 59.27%, while activities of sucrase and urease, pH value and water content in soil increase by 73.71%, 68.60%, 15.09% and 32.95%, respectively. The correlation analysis result shows that there is extremely significant correlation (P<0.01) of content of bacterium in soil with activities of catalase, sucrase and urease, pH value and water content in soil, their correlation coefficient is -0.909, 0.864, 0.868, 0.836 and 0.889, respectively. There is significantly negative correlation (P<0.05) of content of fungus in soil with catalase activity of soil, and extremely significantly positive correlation with sucrase activity and pH value of soil, their correlation coefficient is -0.739, 0.868 and 0.832, respectively. It is concluded that R. repens can change microbial community structure and physicochemical property of soil, which make soil condition more beneficial to R. repens growth.