For assessing the ability of water stress about poplar seedlings, a pot experiment was conducted to investigate the effects of water stress on growth, biomass production and partitioning, photosynthetic pigment and endogenous hormone of one-year-old poplar seedlings .The poplar seedlings are influenced under different water stress conditions .Compared to the control, the basal diameter, height, leaf number and total leaf decrease significantly under either moderate or severe stress, while the basal diameter and height have no significant differences with the control under light stress.With the in-creasing extent of water stress, the dry weight, water stress index (WSI) and total dry weight decrease gradually, howev-er, the root/shoot (R/S) increases significantly.The partitioning index of leaf decreases, but that of root increases gradu-ally.The contents of chlorophyll a (Chla), chlorophyll b (Chlb), chlorophyll (a+b) and carotenoid (Car) decrease sig-nificantly, but the ratio of Chla/b and Chl/Car have an inverse trend with the increasing intensity of water stress.IAA, GA and ZT contents decrease consistently ,while ABA content has the trend of first up and then down with the increasing extent of water stress.Therefore, the poplar seedlings have strong morphological and physiological adaptations under light water stress, but would be weakened significantly under both moderate and severe water stress.%为了探讨杨树苗对干旱胁迫的适应能力，通过盆栽试验，研究了不同干旱胁迫处理对杨树苗生长、生物量分配、光合色素以及内源激素的影响。结果表明：在中度和重度胁迫下，杨树苗的基径、株高、叶片数和总叶面积均显著低于对照，而在轻度胁迫下的基径和株高与对照差异不显著。随着胁迫强度的增加，叶、茎和根的干质量、胁迫指数和总干质量逐渐降低，而根/冠比显著升高；叶的分配指数逐渐降低，根的逐渐升高。叶绿素（ Chla、Chlb和Chl（a＋b））及类胡萝卜素（Car）均随着干旱胁迫增强而呈减小趋势，但Chla/Chlb和Chl/Car的变化趋势相反。生长素、赤霉素和玉米素随着胁迫强度的加剧逐渐降低，而脱落酸先升高后降低。综合分析认为，杨树苗在轻度水分胁迫下具有较强的形态和生理适应性，而在中度和重度胁迫下明显减弱。
展开▼
