中文摘要：

树木年内径向生长动态监测对理解树轮-气候响应的生理机制具有重要意义.本文利用树木径向生长测量仪（Dendrometer）对祁连山东部吐鲁沟国家森林公园内3棵祁连圆柏生长季径向生长进行监测.监测结果发现祁连圆柏树干径向变化呈日周期波动,上午07：00～08：00膨胀到最大值,而在下午16：00～17：00收缩至最小值.监测显示的祁连圆柏主要生长时期为5月初到7月上旬,与早材细胞形成时期一致,在5月底到6月初达到最大生长速率.通过周期法提取日径向增长量（SRI）,并与不同阶段气象因子进行相关分析,发现SRI与收缩阶段气象条件没有显著关系,而与膨胀阶段和增长阶段气象因子显著相关,说明16：00～17：00至07：00～08：00气象条件对径向生长的重要作用.SRI与降水量和相对湿度显著正相关,与水汽压亏缺（VPD）显著负相关,表明本地区祁连圆柏生长受到水分条件限制.相关分析还表明,SRI与平均气温和最低气温负相关.多元线性模型分析显示,相对整个周期,膨胀阶段和增长阶段气象数据能解释更多的径向生长变化,解释量高达87.1％.

英文摘要：

Intra-annual stem radial growth monitoring is important to understand the physiological mechanisms of dendroclimatic research. In this study, the radial increment of Qilian Juniper （Sabina przewalskii Kom.） in the eastern Qilian Mountains was monitored in 2013 using automatic point dendrometer to investigate tree-ring formation and its environmental influence. Three well-growing adult trees in the monitoring site （36°43′21″N, 103°37′59″E, with altitude of 3100m） were continuously monitored during the whole season in 2013. All dendrometers were mounted at about 1.3m height of trees and could get a record every 30min. Three continuous raw data series were obtained and no measuring mistake was found. Gompertz function was used to simulate the cumulative stem radial growth, and the homologous growth rate curves were gotten by the first derivative processing. The period that growth rate exceeds the recording accuracy of instrument （4μm/d） was defined as the main growing period and was used to SRI extraction and subsequent analyses. The entire circadian cycle was divided into three distinct phases： （1） Contraction phase, the period from the morning peak to afternoon trough. （2） Expansion phase, the period from afternoon trough to the next morning peak. （3） Stem radial increment phase （SRI） , part of expansion phase that from the time when the stem radius exceeds the morning maximum to the subsequent maximum. The relationships between SRI and meteorological variables of different phases were assessed using Pearson correlation and Stepwise regression analysis. Meteorological parameters include precipitation （P, mm） , air temperature （T, ℃ ） , relative humidity （RH,%） , soil temperature （ST, ℃ ） , water content （WC, m^3/m^3） , and vapor pressure deficit （VPD, kPa）. Dendrometer records showed that the maximum of expansion phase appeared at 07：00- 08：00 and minimum of contraction phase at 16：00-17：00. Gompertz function simulated well and the goodne