天目山柳杉树干液流动态研究

Dynamics of Stem Sap Flow of Cryptomeria fortunei in Mount Tianmu

利用热扩散式液流探针(TDP)对天目山柳杉(Cryptomeria fortunei)树干液流进行连续测定,同步测定太阳有效辐射、空气温度、空气湿度等气象因子,探讨环境因子与树干液流之间的内在响应关系。结果表明:柳杉树干液流速率呈单峰曲线;柳杉液流在7:00-8:00启动,12:30-14:00达到峰值,夜间仍然存在微弱的液流变化;不同天气柳杉液流日变化差异明显,晴天液流启动较早峰值最大,阴雨天气液流启动延迟峰值较小;柳杉液流速率与光合有效辐射、空气温度、水汽压亏缺呈极显著正相关关系,而与空气湿度呈极显著负相关关系,其相关性大小排序依次为:空气温度>水汽压亏缺>空气湿度>光合有效辐射。

Stem sap flow of Cryptomeria fortunei was determined by thermal dissipation probe （TDP） in Mount Tianmu, Zhejiang province. Andphotosynthetic available radiation（PAR）, air temperature and air humidity was measured as well for studying their relationship. Results showed thatsap flow started at 7：00 to 8：00, topped at 12：30 to 14：00 and had a weak activity in the night. It had obvious difference of diurnal change of sap flowunder different weather conditions, in sunny day it started earlier and had higher peak, however in cloudy and rainy day it started later and had a lesspeak. The determination indicated that stem sap flow had significant positive relation with PAR, air temperature and vapor pressure deficit （VPD）, butnegative with air humidity.