<正>于2002午8月~2003年7月对四川西部理县干旱河谷区土壤水分状况进行了定位研究。结果表明：在理县干旱河谷区，不向海拔高度0~50cm土层土壤平均含水量总的变化趋势是阴坡比阳坡高，而土壤水分空间异质性阳坡比阴坡大。同一坡向不同海拔的土壤含水量变化为2050m处的最高，1850m处的次之，1450m处再次之，1650m处最少，表明了在干旱区河谷的两岸坡面上部土壤水分状况最好。在坡面下部靠近河流处次之，中下坡水分条件最差。相同海拔高度，不同坡向土壤含水量都表现为随着土层深度的增加土壤含水量增加的趋势，且30~50cm土层的土壤含水量最高。

The dynamic changes of endogenous hormone contents in Betula luminifera were mesured by ELISA during adventitious buds and roots formation, which were cultured on the modified MS medium of plus with 4.5 mg/L BA and 0.01 mg/L NAA and on modified WH medium plus with 3.0 mg/L BA and 1.5 mg/L NAA respectively. It was showed that the significant effect between endogenous hormone and exogenous hormone in vitro culture during morphogenesis. The results provided the properly combination for setting in vitro culture system. It was also proofed that exogenous hormone endogenous hormone to regulate the development of adventitious buds and roots during morphogenesis. With the increasing endogenous hormone, including ZR, ABA, IAA, promoting the development of adventitious buds, and with the increasing endogenous hormone, including IAA, ABA, iPA, promoting the formation and development of root system.