华北平原主要造林树种107杨扦插苗夏季茎流及耗水特性

Sap flow and water consumption of Populus×euramericana '74/76' saplings from cuttings planted on the North China Plain

采用以热平衡为原理的Dynamax包裹式茎流测量系统,于2008年夏季对107杨Populus×euramericana‘74/76’扦插苗的液流变化进行连续监测,利用实验区自动气象站同步检测光合有效辐射、气温和相对湿度等气象因子,结合人工记录的天气状况,分别选取3种最典型的天气条件,分析了107杨扦插苗的茎流变化、茎干耗水量及其与气象因子的关系。结果表明:在不同天气条件下,液流日变化波动曲线及其主要影响因子各异,但光合有效辐射始终是液流变化的主导因子。茎干液流通量密度的变化是各种气象因子综合作用的结果。107杨扦插苗日耗水量的总体变化趋势是从晴天、阴天到雨天依次减少,其平均值分别为1064.126,567.975和405.914g.d-1。

Simultaneous measurement with a heat balance and sap flow measuring system（Dynamax Inc.） to monitor the sap flow of Populus × euramericana ＇74/76＇ and with an automatic weather recording system to record meteorological factors,such as the photosynthetically active radiation （PAR）,air temperature,and relative humidity,was undertaken. According to weather records,the three most representative weather conditions （sunny,cloudy,and rainy days） were used to analyze the relationship of water use and meteorological factors. Results showed that PAR was always the dominant factor influencing sap flow,but sap flow diurnal variation and the main factors affecting it differed with weather conditions. Differences in sap flow density were the result of multi-meteorological factors,and the overall water use for saplings was in the order：sunny days cloudy days rainy days.