外来种加拿大一枝黄花与土著种芦苇根际土壤线虫群落比较

Soil Nematode Communities Associated with Exotic Solidago Canadensis L. and Native Phragmites Australis

为比较外来入侵种加拿大一枝黄花(Solidago canadensis L.)与土著种芦苇(Phragmites australis)根际土壤线虫多样性和群落结构的差异,笔者分别于2009年4月(出苗期)、9月(开花期)和12月(枯萎期)对杭州下沙加拿大一枝黄花群落及相邻芦苇群落的根际土壤线虫进行调查.结果显示:两种植物根际土壤线虫群落存在差异,并且这种差异与采样时间(植物生长阶段)有关.加拿大一枝黄花根际土壤的线虫数量、属丰富度和多样性在出苗期和开花期与芦苇根际没有显著差异,而在枯萎期则显著高于芦苇.加拿大一枝黄花根际土壤线虫营养多样性在三个生长阶段均显著高于芦苇.在出苗期和开花期加拿大一枝黄花根际植食性线虫比例明显低于芦苇根际,食真菌线虫比例则明显高于后者;在枯萎期,加拿大一枝黄花根际土壤线虫的食真菌线虫比例明显高于芦苇根际土壤,而食细菌线虫比例趋于降低.非参数多变量排序(MDS)表明,加拿大一枝黄花根际土壤线虫群落结构与芦苇在其三个生长阶段均差异明显,其中枯萎期差异最大.上述结果表明外来植物入侵在一定程度上改变了土壤线虫多样性、功能多样性和营养结构,这种改变可能导致土壤生态系统中营养源流向和路径发生变化,并促进外来植物进一步入侵.

To compare the diversity and community structure of soil nematodes between exotic Solidago canadensis L. and native Phragrnites australis, the experiment investigated the soil nematodes in two plant communities at Xiasha Hangzhou in April（emergence period）, September（flowering period） and December（withering period） 2009. The results show that there exist dissimilarities in nematode communities between exotic S. canadensis L. and native P. australis associated with plant growth stage. There are no significant difference in density, genus richness and diversity of soil nematode communities between S. canadensis and P. australis in emergence and flowering period. In withering period, the density, genus richness and diversity of soil nematode are higher in the soil colonized by S. canadensis L. than in the soil under P. australis. The trophic diversity of nematode community is significantly higher in the soil colonized by S. canadensis L. than in the soil under P. australis in all three growth stages. Nematodes in the soil colonized by S. canadensis L. have higher proportion of fungivores and lower proportion of herbivores in emergence and flowering period compared to the soil of P. australis. Significant increase in the proportion of fungivores and significant decrease in the proportion of bacterivores are detected in the soil colonized by S. canadensis L. compared to the soil under P. australis in withering period. The results of MDS show the dissimilarities in nematode communities between exotic S. canadensis L. and native P. australis in all three growth stages, and the greatest dissimilarities are found in withering period. The results suggest that the invasion of the exotic plant has changed the diversity, trophic diversity and trophic structure of soil nematode, which may change the direction and path of nutrition sources of soil ecosystem, and promote exotic plant further invaded.