中文摘要：

干旱等极端气候事件增加是全球气候变化的重要特征之一，其生态系统效应的研究对预测未来生态系统格局和功能具有重要意义. 通过野外模拟分别发生在植物生长季初期和旺期的百年一遇极端干旱事件，研究了青藏高原高寒草甸植物群落的开花物候对极端干旱的响应. 结果表明：（1）生长季初期的极端干旱显著提前半花期2.3 d（P=0.023），生长季旺期极端干旱显著缩短花期持续时间2.3 d（P=0.042）；（2）开花物候对极端干旱的响应与植物本身繁殖季节性有关；（3）不同功能群开花物候对极端干旱响应不一，双子叶杂类草最敏感，其半花期显著提前2.8 d（P=0.049），莎草类和禾草类表现出一定抵抗力；（4） 极端气候事件对植物物候产生的生态效应强烈，与其他研究揭示的趋势性降水变化产生的生态效应有显著区别. 图4 表3 参58

英文摘要：

Exceptional damaging climate events including drought have become a major feature in current global climate change. Understanding the ecological responses of ecosystem to extreme events could contribute to prediction of ecosystem pattern and function in future. In this study we artificially imposed extreme droughts at the beginning and the peak of growing season on an alpine meadow plant community on the eastern edge of the Qinghai-Tibetan Plateau to observe the flowering responses. The results showed that （1） extreme drought at the beginning of growing season significantly advanced the mid-flowering date of alpine meadow plant by 2.3 d; extreme drought in the peak growing season significantly compressed the flower duration by 2.3 d; （2） the flower phenology responses of species were related to the seasonality of their reproduction; （3） after treatments functional groups reacted inconsistently, with the forbs sensitive to the extreme drought while the sedges and grasses not; （4） the intense ecological responses of plant flowering to extreme climate change implied the importance of researches regard to extreme events. Fig 4, Tab 3, Ref 58