采用磷脂脂肪酸(PLFAs)分析法比较了红毛草[Rhynchelytrum repens (Willd.) C. E. Hubb.]非入侵区、轻度入侵区和重度入侵区土壤微生物群落结构的差异,并对不同程度入侵区土壤部分理化指标的差异进行比较;在此基础上,对土壤中不同类型微生物含量与部分理化指标的相关性进行分析。结果表明:在不同程度入侵区土壤中共检测到37 种微生物,包括28 种细菌、4 种放线菌、4 种真菌和1 种原生动物,其中,细菌含量最高。6 种微生物的PLFAs 含量较高,且它们在3 类入侵区均有分布;27 种微生物的PLFAs 含量较低,且它们在3 类入侵区也均有分布;4 种微生物的PLFAs 含量较低,且它们仅分布在个别入侵区。随红毛草入侵程度加剧,土壤中细菌、真菌和原生动物的含量均逐渐升高, 且它们在重度入侵区土壤中的含量分别较非入侵区增高11. 34%、19. 60%和13. 95%;并且,土壤中的微生物种类也逐渐升高。随着红毛草入侵程度的加剧,土壤的过氧化氢酶活性逐渐下降,蔗糖酶和脲酶活性以及pH 值和含水量均逐渐升高,而纤维素酶活性变化较小;与非入侵区相比,重度入侵区土壤的过氧化氢酶活性下降59. 27%, 而蔗糖酶和脲酶活性以及pH 值和含水量分别升高73. 71%、68. 60%、15. 09% 和32. 95%。相关性分析结果表明:土壤中的细菌含量与过氧化氢酶、蔗糖酶和脲酶活性以及pH 值和含水量均存在极显著相关性(P<0. 01),相关系数分别为-0. 909、0. 864、0. 868、0. 836 和0. 889;土壤中的真菌含量与过氧化氢酶活性存在显著负相关(P<0. 05), 与蔗糖酶活性和pH值存在极显著正相关,相关系数分别为-0. 739、0. 868 和0. 832。研究结果显示:红毛草能够改变土壤的微生物群落结构及理化性质,使土壤条件更利于红毛草的生长。

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.