中文摘要：

根据1963–2007年中国物候观测网西安观测站的物候和气温、降水资料,分析了西安站34种木本植物春季展叶始期、展叶盛期、始花期和盛花期等4个关键物候期的变化趋势、对气候变化的阶段响应特点及其与气温、降水变化的关系。结果表明,1963年以来,西安地区气温呈显著上升趋势,特别是1994年前后,气温发生明显突变,上升趋势更加明显;西安春季物候变化主要呈现提前趋势。在45年中,观测到的34种植物的展叶始期平均提前1天,展叶盛期平均提前1.4天,始花期平均提前9天,盛花期平均提前12天;以突变点为界,34个物种1995–2007年的4种物候期比1963–1994年平均提前了4.34±0.77天;春季物候期的早晚主要受春季气温的影响,特别是春季物候期发生当月和上一月的平均气温对物候期的影响最为显著。叶物候和物候发生期前一月的降水量有较为明显的相关关系,花物候期和降水的关系不明显。

英文摘要：

Aims Few studies have investigated phenological response to climate change in Western China to understand ecological responses to climate change and evaluate phenological differences on a regional scale.We analyzed spring phenological data from 34 woody plants for the past 45 years in Xi＇an.Our objectives were to determine the relationships between plant phenology and air temperature change and to explore the response of spring phenophases to abrupt climate change in Xi＇an.Methods The Mann-Kendall test was used to describe the trend of temperature change and the specific point of climate change.The trends of spring phenophases were described by simple linear regression.The significance of correlation coefficients between phenophases and both temperature and precipitation were examined by t-tests.Important findings Four spring phenophases generally showed advancement,and the characters of phenological change were consistent with climate change,even abrupt climate change.Statistically significant correlation was found between the changes of spring phenophases and the temperatures of one or several months before the phenophase onset.The mean monthly temperature of the onset month or the prior month was the key factor impacting the spring phenophase.Moreover,there was a strong correlation between leaf phenophase and monthly precipitation of one month before the phenophase onset,while the correlation between flower phenophase and precipitation is not obvious.