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外来植物入侵对土壤生物多样性的影响已成为生态学领域的研究热点之一。运用Biolog技术和氯仿熏蒸浸提法研究了黄顶菊入侵对土壤微生物群落功能多样性及土壤微生物量的影响。结果表明,黄顶菊入侵后土壤微生物代谢活性显著升高;土壤微生物群落平均吸光值(AWCD)的变化趋势为:入侵地根际土(RPS)>入侵地根围土(BS)>未入侵地(CK),且差异显著;而CK的功能多样性指数(H)高于BS,RPS亦高于BS,差异均显著(P<0.05)。主成分分析结果表明,黄顶菊入侵使土壤微生物群落的碳源利用方式和代谢功能发生改变。对不同碳源利用的分析结果表明,糖类、氨基酸类、羧酸类和聚合物为土壤微生物利用的主要碳源。入侵样地BS和RPS的微生物量碳分别比CK高27.05%、121.52%;BS和RPS的微生物量氮分别比CK高37.40%、79.80%。相关性分析表明,AWCD与微生物量碳和微生物量氮均呈极显著正相关(P<0.01)。由此可知,黄顶菊入侵增强了入侵地土壤微生物代谢活性,降低了土壤微生物群落的功能多样性,增加了土壤微生物量碳、氮水平。
The impact of invasive plant invasions on soil biodiversity has become one of the hot topics in the field of ecology. Biolog and chloroform fumigation were used to study the effects of flaveria bidentis invasion on functional diversity of soil microbial community and soil microbial biomass. The results showed that the metabolic activity of soil microorganisms increased significantly after invasion of flaveria bidentis, and the trend of soil microbial community average light absorbance (AWCD) was as follows: invasion rhizosphere soil (RPS)> invasion rhizosphere soil (BS)> uninvaded land CK), and the difference was significant. The functional diversity index (H) of CK was higher than that of BS and RPS was also higher than that of BS (P <0.05). Principal component analysis showed that the invasion of Flaveria bidentis changed the utilization pattern of carbon sources and the metabolic function of soil microbial communities. Analysis of the utilization of different carbon sources showed that carbohydrates, amino acids, carboxylic acids and polymers were the main carbon sources for soil microbial utilization. The microbial biomass carbon in BS and RPS was 27.05% and 121.52% higher than that in CK respectively. The microbial biomass nitrogen in BS and RPS was 37.40% and 79.80% higher than CK, respectively. Correlation analysis showed that AWCD had a significantly positive correlation with microbial biomass carbon and microbial biomass nitrogen (P <0.01). Therefore, invasion of flaveria bidentis increased soil microbial metabolic activity in invaded soil, reduced functional diversity of soil microbial community and increased soil microbial biomass carbon and nitrogen.