中文摘要：

植物物候特征对环境条件的季节和年际变化具有较强的指示作用，因此研究植物物候特征对环境条件变化的响应，对理解植物和环境之间的相互作用关系、植物的适应机制和生存策略，以及应对全球变化都具有重要的意义。该研究基于2009-2011年高寒矮生嵩草（Kobresiahumilis）草甸养分水分控制实验的植物物候观测数据资料，采用巢式方差分析、物候指数和聚类分析方法，开展了高寒矮生嵩草草甸主要植物物候特征对养分和水分添加的响应研究。结果表明：（1）养分添加处理之间植物返青期和枯黄期均无显著差异，但养分添加中氮磷处理对主要物种作用较明显，使莎草科、禾本科、杂类草主要代表植物的返青期和枯黄期推迟。（2）增雪处理效应明显，主要优势物种无论是何种养分添加，在增雪处理后均表现出花期物候提前的趋势（p〈0．01），同时增雪处理使杂类草植物返青期显著提前p〈0．05）。增水处理对植物的作用效果并不一致，其中垂穗披碱草（Elymusnutans）和双柱头蔗草（Scirpusdistigmaticus）的枯黄期显著推迟0〈0．05），而杂类草枯黄期提前。（3）养分添加后，不同物种的物候特征表现出显著差异（p〈0．01），例如雪白委陵菜（Potentillanivea）枯黄期显著推迟p〈0．05），而双柱头蔗草的枯黄期显著提前p〈0．05），但物种对养分添加响应的差异以植物类群为单位，禾本科植物表现为返青期推迟，而莎草科植物表现为返青期提前。（4）矮生嵩草草甸主要植物营养生长期与果后营养期持续天数之间呈负相关关系，主要植物物候特征经聚类分析可以分为3个类群，3个类群经氮磷钾、钾和氮钾三个养分添加处理后植物物候特征变化较大。研究表明，高寒矮生嵩草草甸植物物候特征在物种水平响应和水分添加后的响应表现出较大差异，

英文摘要：

Aims Phenology is a sensitive, integrated indicator of environmental changes. It is important to research the re- sponses of phenological characteristics to environmental changes for understanding interactions between plants and environment, adaptive mechanisms and survival strategies. Our objective is to examine how phenological characteristics of plants respond to nutrient and water conditions in the eastern Qinghai-Tibet Plateau. Methods Plant phenological characteristics in alpine Kobresia humilis meadow following nutrient and water additions from 2009 to 2011 were quantitatively analyzed by the methods of nested analysis of variance, phono- logical index and cluster analysis. Important findings There were no significant differences in either green-up date or senescence date of plants with nutrient addition, but these dates in several dominant species of grasses, sedges and forbs were postponed following N and P addition. The treatments of nutrient and winter moisture addition moved up flowering dates of dominant species （p 〈 0.01） and green-up dates of forbs （p 〈 0.05）. Effects of nutrient and summer moisture addition were inconsistent. The senescence dates ofElymus nutans and Scirpus distigmaticus were significantly postponed （p 〈 0.05） and forbs were postponed. Phenological characteristics of different species had significant differences with nutrient addition （p 〈 0.01）： the senescence dates ofPotentilla nivea were significantly postponed （p 〈 0.05）, thesenescence dates of Scirpus distigmaticus were significantly moved up （p 〈 0.05）, but the different phenology re- sponses of plants to the nutrient addition were based mainly on plant groups, with the green-up dates of grasses mostly postponed but the green-up dates of sedges moved up. Continuance of vegetative growth and vegetative period after fruiting were negative correlated. Phenological characteristics of plants were divided into three groups by cluster analysis. Phenological characteristics ~f the treatment of n