中文摘要：

本试验以短花针茅荒漠草原为研究对象,通过控制性增温与施肥试验,研究了短花针茅在增温施氮4 a后各处理其生殖物候与光合作用的变化。研究结果表明：a）短花针茅Pn日动态呈双峰曲线,在不同处理下的2个高峰值存在显著差异（p〈0.05）,施氮处理显著高于对照处理;各环境因子中,PAR是影响光合作用最为强烈的环境因子。b）施氮处理对短花针茅的开花时间有显著影响（p〈0.05）,其延迟了1.3d;而结实时间对增温施氮交互作用有显著响应（p〈0.05）,其延迟了1.89d;生殖生长持续时间也对增温和增温施氮交互作用有显著响应（p〈0.05）,分别延迟了1.37d和1.39d。

英文摘要：

This study was conducted to analyze the effects of warming,nitrogen addition and the compound effect of warming and nitrogen addition on Stipa breviflora in the Desert Steppe in Inner Mongolia.By using a L i26400 portable photosynthesis system and uses the grading method to carry on the observation and the record to the Stipa breviflora reproduction phenology,the observed data carries on the growth fitting with the MatLab software,is carrying on the computation reproduction phenology and the seasons various times number of days..zhe results showd that a） the Pn of Stipa breviflora is presented double-peak for different treatments and has significantly advanced of Peak（p〈0.05）,Nitrogen addition significantly advanced highter than control.b） Nitrogen addition significantly advanced the flowering time of Stipa breviflora（p〈0.05）,prolonged the flowering time of Stipa breviflora to 1.3 days;Warming and nitrogen addition significantly advanced the friuting time of Stipa breviflora（p〈0.05）,prolonged the flowering time of Stipa breviflora to 1.89 days;Warming and the compound effect of warming and nitrogen addition significantly advanced the reproductive duration of Stipa breviflora（p〈0.05）,prolonged the reproductive duration of Stipa breviflora to 1.37 days and 1.39 days.