水分胁迫下白杨双交杂种无性系苗木生长研究

Study on seedling growth of white poplar hybrid clones under the conditions of water stress

以白杨双交杂种无性系为材料 ,在水分胁迫条件下 ,对无性系幼苗的生长进行了研究。结果表明 ,水分胁迫对叶片、苗高和生物量生长均产生显著影响。轻度水分胁迫即可使苗木叶面积生长受到抑制 ,随着水分胁迫的加剧 ,叶片速生期有提前的趋势 ,速生期持续时间有延长趋势 ,但受胁迫的苗木绝对生长速率较低 ,没有明显的生长高峰期出现 ,造成单叶面积随水分胁迫的发展而显著减小。水分胁迫对叶面积的影响大于对苗高生长的影响 ,在供水量为 6 0 %时 ,苗高生长才受到明显抑制。根、茎、叶干物质积累以供水量 80 %最为适宜 ,供水量进一步下降 ,各部分干物质积累逐渐受到抑制 ,茎和叶生物量受抑制最明显 ,根生物量受影响相对较小 ,因此随着水分胁迫的发展 ,茎 根比值表现为明显的下降趋势。不同无性系在各生长指标上和各指标随水分胁迫下降幅度上均存在着显著差异。大部分指标间表现为正相关关系 。

With double cross hybrid clones of white poplar as the experimental materials, the seedling growth of the clones was studied under the conditions of water stress. The result showed that water stress had impact on leaf growth, seedling height and biomass. Leaf growth of the seedling was restrained by water stress lightly. With the development of water stress, the period of leaf rapid growth moved up and the duration of the period of rapid growth protracted. But the rate of growth of leaf stressed was lower and there was not obvious peak, the single leaf area reduced obviously with development of water stress.The effect of water stress on leaf area was greater than on height growth.The height growth of seedling was obviously restrained when the soil water content droped to 60%.The fitting soil water content for the biomass accumulation of root, stem and leaf was 60% and with more drop of water content the accumulation of dry material of plant was restrained gradually. The influence of water stress on biomass of stem and leaf was more obvious than on the biomass of root. Therefore,with developing of water stress, the ratio of stem and root was reduced distinctly. Significant differences existed among clones on growth indexes and drop extent of the indexes with water stress. There were positive correlation among most indexes. That showed adaptability of the indexes to water stress was accordant.