中文摘要：

利用树木径向生长测定仪、自动气象站和土壤水分自动监测仪,在黑河下游胡杨河岸林内,同步监测了胡杨径向生长日变化和太阳辐射、气温、空气相对湿度及主要根系层土壤水分动态等环境因子.结果表明：胡杨径向生长日变化呈抛物线形,每日16：00～20：00时达到最低值点,随后逐步上升至翌日06：00～09：00时达到最高值点,完成一个由收缩期、膨胀恢复期和生长期3阶段构成的日变化周期;不同季节,胡杨径向生长变动幅度存在较大差异.就监测样树而言,不同胡杨个体,胸径越大,日净生长量越大.对各环境因子统计表明,胡杨径向生长日变化与总辐射、气温和土壤体积含水率呈负相关关系,与空气相对湿度呈正相关关系.各环境因子对胡杨径向生长影响存在延时滞后作用,特别是土壤水分条件.

英文摘要：

Using the point-dendrometer,automatic meteorological station and the soil water content monitor,the sub-diurnal radial growth of Populus euphratica,intensity of illumination,air temperature,relative humidity and the soil water bulk content in the main root zone were measured synchronously in the riparian divers-leaf poplar forest in the downstream of Heihe River.It is revealed that：1）the sub-diurnal radial growth of P.euphratica presents a parabola pattern,reaching the lowest in 16：00-20：00,and then increasing gradually to the highest in 06：00-09：00 in the next morning.This diurnal cycle can be divided into contraction,expansion and increment phases;2）the sub-diurnal radial growth of P.euphratica has large difference among different seasons and specimens.The larger of the specimen＇s diameter,the larger of the net increment is;3）the intensity of illumination,air temperature and the soil water bulk content have negative relations to the sub-diurnal radial growth of P.euphratica,and the relative humidity has a positive relation.And among them,the relationships of the intensity of illumination,air temperature and the soil water bulk content at the 20 cm depth reach to a high level of significance.These environmental factors,especially the soil water condition,are all likely have the lagged effect on the radial growth of P.euphratica.