基于Biolog技术的外来种意大利苍耳与本地种苍耳根际土壤微生物功能多样性的比较

摘要

通过盆栽试验,采用Biolog技术对比研究了外来入侵植物意大利苍耳与本地植物苍耳根际土壤微生物群落功能多样性及对土壤碳源利用的差异,以未种植任何植物土壤为空白对照.结果表明,入侵植物意大利苍耳的土壤微生物群落功能多样性显著高于本地植物苍耳的土壤微生物群落功能多样性.意大利苍耳显著提高了根际土壤微生物31种碳源的平均颜色变化率(AWCD)(72 h,P＜0.05),AWCD变化规律如下:意大利苍耳＞苍耳＞CK(对照);意大利苍耳的Shannon多样性指数(H)、优势度指数(D)和丰富度指数(S)均显著高于苍耳和空白对照,与苍耳相比,意大利苍耳的H,D,S分别增加了3.13％,0.77％和21.67％,与CK相比,意大利苍耳的H,D,S分别增加了4.59％,0.89％和35.18％,CK最低;碳代谢指纹图谱分析表明意大利苍耳和苍耳的碳源利用存在显著差异,意大利苍耳显著提高了根际微生物对胺类、酚酸类、氨基酸类和糖类等碳源的利用;主成分分析(PCA)表明,两种植物根际土壤微生物碳源利用特征出现分异,意大利苍耳集中在第一主成分,得分系数3.3103,苍耳主要分布在第二主成分,得分系数-1.9616;糖类物质、羧酸类化合物、多聚物和氨基酸类是根际微生物利用的主要碳源.改变入侵地土壤微生物群落的结构与功能,提高根际土壤微生物的代谢活性,形成对自身有益的土壤微生态环境可能是意大利苍耳成功入侵的原因之一.%The aim of this research was to analyze differences in functional diversity and the carbon source utilization of the rhizosphere soil microbial community between the invasive plant Xanthium italicum and its native partner,Xanthium sibiricum.The two plants were cultivated in a put experiment and their soil microbial communities were analyzed using the Biolog technique.Soil with no plants served as the blank control (CK).The results indicated that the functional diversity of the soil microbial community was significantly higher for the invasive plant X.italicum than for the native plant X.sibiricum.The rhizosphere soil microbes from X.italicum significantly increased the average well color development (AWCD) (72 h,P＜0.05) for 31 carbon sources.The treatments were ranked,from largest change in AWCD to smallest,as follows:X.italicum＞X.sibiricum＞CK.The values of Shannon's diversity index (H),Simpson's dominance index (D),and substrate richness index (S) were significantly higher for X.italicum rhizosphere soil microbes than for those of X.sibiricum and CK.The Shannon's indexes (H,D,S) of the X.italicum rhizosphere soil microbial community were 3.13％,0.77％,and 21.67％ higher,respectively,than those ofX.sibiricum;and 4.59％,0.89％,and 35.18％ higher,respectively,than those of CK.The lowest values of H,D,and S,were in CK.The carbon metabolic fingerprint analysis showed that carbon source utilization differed significantly between X.italicum soil microbes and X.sibiricum soil microbes.The rhizosphere soil microbes of X.italicum showed the highest utilization of amines,phenolic acids,amino acids,and sugars.A principal component analysis (PCA) showed that the carbon utilization features of soil microbial communities differed between the two plants.The soil mi-crobial community of X.italicum was concentrated in the first principal component (score coefficient,3.3102) and that of X.sibiricum was concentrated in the second principal component (score coefficient,-1.9616).Carbohydrates,carboxylic acids,polymers,and amino acids were the major carbon sources utilized by rhizosphere soil microbes.Therefore,the reasons for the successful invasion for X.italicum could include:(1) changes in the structure and function of soil microbial communities;(2) increased metabolic activity of rhio-sphere soil microbes;and (3) the formation of a soil microenvironment that benefits its own growth.