中文摘要：

以感染内生真菌的人工禾草高羊茅为研究对象,通过比较不同CO2浓度和氮素处理下,感染内生真菌和不染菌植物在种子萌发和营养生长等方面的差异,探讨感染内生真菌的高羊茅对CO2升高的响应.试验结果表明,（1）内生真菌感染影响了宿主种子萌发对CO2浓度升高的响应,CO2浓度升高使得内生真菌感染促进了宿主植株的胚芽和胚根的伸长;（2）CO2浓度升高使高羊茅地下生物量显著增加,只是内生真菌感染植株的地下生物量显著低于不染菌植株;CO2浓度升高使不染菌植株地上部分氮含量显著降低,而对染菌植物无显著影响;（3）内生真菌对宿主响应CO2的影响与氮素供应水平有关,在高浓度CO2和氮素供应下内生真菌感染显著降低了宿主植物的分蘖数,而在高浓度CO2和缺氮供应下,染菌植株的可溶性糖含量显著高于不染菌植株;（4）内生真菌对宿主响应CO2的影响与氮素供应形态有关,在高浓度CO2和硝态氮供应下,内生真菌感染显著降低了宿主植物的地上生物量,而在铵态氮供应下,染菌植株的总游离氨基酸含量显著高于不染菌植株.

英文摘要：

In the present study, we examined how endophyte infection affected responses of the host grass, tall feseue, to elevated CO2, and whether this effect was related to the concentration and the form of nitrogen. The results showed that, （1） endophyte infection affected the response of seedling growth to elevated CO2. The elongation of both coleoptile and radicle were significantly improved in E ＋ （endophyte-infected） seeds while those in E- （endophyte-free） seeds were not affected by elevated CO2. （2） The root biomass in- creased under elevated CO2, onlyit was significantly lower in E＋ than that in E- plants. E- plants had lower shoot nitrogen concentration under elevated CO2 than that under ambient CO2, but this effect was largely absent in E＋ plants. （3） The effect of endophyte infection on the response of host plants to elevated COe was closely related to the concentration and the form of nitrogen. With elevated CO2 and nitrogen supply, lower tillers in E ＋ plants. With elevated CO2 and nitrogen deficiency, endophyte infection resulted in higher soluble sugar con- centrations in E＋ plants. （4） With elevated CO2, endophyte infection significantly decreased root biomass with nitrate supply but increased total free amino acids of host plants with ammonium supply.