外来入侵植物薇甘菊的2种化感物质对土壤氮循环的影响

Effects of Two Allelochemicals in Alien Invasive Plant Mikania micrantha on Soil Nitrogen Cycling

为揭示薇甘菊(Mikania micrantha)通过化感作用影响土壤养分循环的入侵机制,通过外源添加薇甘菊2种化感物质(绿原酸和β-石竹烯),测定其对土壤氮素和氮循环功能菌的影响。结果表明,添加绿原酸和β-石竹烯均显著降低了土壤铵态氮含量,添加绿原酸显著提高了土壤硝态氮含量,β-石竹烯则对土壤硝态氮含量无显著影响。其主要原因是绿原酸和β-石竹烯均显著抑制了自生固氮菌和氨化细菌的繁殖,绿原酸显著促进了氨氧化细菌和硝酸化细菌的繁殖,而β-石竹烯仅促进了氨氧化细菌的繁殖,对硝酸化细菌没有影响。因此,薇甘菊能通过化感物质绿原酸和β-石竹烯影响氮循环功能菌的繁殖从而影响土壤氮循环。

In order to reveal the invasion mechanism of Mikania micrantha affecting soil nutrient circulation through allelopathy,the effects of two allelopathic substances from M.micrantha(i.e.chlorogenic acid and β-caryophyllene)on soil nitrogen and related functional bacteria of nitrogen cycle were studied using exogenous addition culture experiments.The results showed that both chlorogenic acid andβ-caryophyllene significantly reduced the content of soil ammonium nitrogen,and chlorogenic acid increased significantly the content of soil nitrate nitrogen,whileβ-caryophyllene had no significant effect.The main reason was that both chlorogenic acid and β-caryophyllene significantly inhibited the reproduction of azotobacter and ammonifying bacteria,and chlorogenic acid significantly promoted the growth of ammonia-oxidizing bacteria and nitrifying bacteria,while β-caryophyllene only promoted the reproduction of ammonia-oxidizing bacteria,and had no effect on nitrifying bacteria.So,it was concluded that M.micrantha invasion could affect the growth of functional bacteria associated with nitrogen cycle through the allelochemicals,thus altered the soil nitrogen cycle.