Abstract: The Achnatherum inebrians-Epichloë endophyte symbiosis is a unique model for studying the aboveground and belowground biological linkages in ecosystems,but little is known about the effects of this symbiosis on soil enzyme activities and nutrient content at different growth periods. In this study,we collected soils from drunken horse grass infected with endophytic fungi (E+) and without endophytic fungi (E-) during periods of dormancy and regeneration,and determined the enzyme activities and nutrient contents of E+ and E-drunken horse grass habitat soils. The results showed that endophytic fungi significantly increased the available phosphorus content of drunken horse grass soils by 34.7% and 36.7% over E-drunken horse grass during the periods of dormancy and regeneration,respectively. In addition,endophytic fungi increased the nitrate nitrogen content of drunken horse grass soil during the regeneration period by 32.3% compared to E-soil. During the regeneration period,the increased temperature enhanced the activities of sucrase and alkaline phosphatase in E+ and E-drunken horse grass soils,which in turn increased the effectiveness of soil N and P,and provided essential nutrients for the growth and regeneration of drunken horse grass. The above results indicated that the endophytic fungi improved soil fertility by regulating soil nutrients,and the changes in soil enzyme activities and nutrient contents during the regeneration period ensured the successful regeneration of drunken horse grass. This study provides a theoretical basis for a deeper understanding of the ecological role of grass-endophytic fungi symbiosis.

Key words: Achnatherum inebrians, Epichloë gansuensis, Soil enzyme activities and nutrients content, Dormancy and regeneration period

摘要： 醉马草-内生真菌共生体是研究生态系统中地上与地下生物联系的独特模式，但该共生体对不同生长期土壤酶活性和养分含量的影响知之甚少。本研究采集休眠期和返青期携带内生真菌(E+)和未携带内生真菌(E-)醉马草的生境土壤，测定E+和E-醉马草土壤酶活性和养分含量。结果表明：在休眠期和返青期，内生真菌显著增加了醉马草土壤速效磷含量，较E-醉马草分别提高34.7%和36.7%。在返青期内生真菌增加了醉马草土壤硝态氮含量，较E-醉马草提高了32.3%。此外，返青期温度升高增强了E+和E-醉马草土壤蔗糖酶和碱性磷酸酶活性，这提高了土壤N、P的有效性，为醉马草的生长返青提供基本养分。以上结果表明内生真菌通过调节土壤养分提高土壤肥力，返青期土壤酶活性和养分含量的变化保证了醉马草顺利返青。本研究为深入理解禾草-内生真菌共生体的生态学作用提供理论依据。

关键词: 醉马草, 内生真菌, 土壤酶活性和养分含量, 休眠期和返青期