<正>选择３种不同类型的杨树无性系（Ｉ－６９、ＮＬ－８０１０５、ＮＬ－８０３５１），在人为控制条件下进行不同程度的淹水胁迫试验，结果表明：在胁迫条件下３种杨树无性系生物量累积受到明显抑制，冠根比降低，叶片硝酸还原酶（ＮＲ）活性显著下降，叶片相对质膜透性（ＲＰＰ）明显升高，叶绿素含量以及叶片含水量（ＲＷＣ）降低，无性系之间的各性状表现有所差异，与对照相比，在强淹水胁迫中Ｉ－６９杨表现最好，其次是１０５杨，而３５１杨最差；在弱淹水胁迫中，３５１杨表现最佳，Ｉ－６９杨和１０５杨相差无几。统计分析显示，ＮＲ活性和ＲＰＰ两个指标与生物量之间存在显著相关关系

Based on the research of the seedlings （I－69，NL－80105，NL－80351）under the flooding stress and the waterlogging stress，results showed that, (1)flooding and waterlogging stresses seriously inhibited the growth in biomass of all three poplar clones, and the rate of the biomass would decrease with the lasting course of the stress, which were in the order of treatment A