水分胁迫对霸王苗期叶水势和生物量的影响

Effect of soil water stress on leaf water potential and biomass of Zygophyllum xanthoxylum during seedling stage

用盆栽试验测定了不同水分胁迫下强旱生植物霸王苗期的叶水势和生物量。结果表明,随着土壤含水量的下降,霸王的叶水势逐渐下降。轻度和中度水分胁迫下,霸王的生物量没有受到抑制,而重度水分胁迫下生物量明显减少(P<0.05)。生物量在个体中的分配比例随着土壤水分亏缺程度的增加呈现有规律的变化,表现为根冠比增大;地上部分为茎的比例增加而叶片的比例减少,黄叶的比例增加而绿叶的比例减少;地下部分为根系直径<2mm/直径>2 mm增加。苗期霸王可通过自身调节在不同水分条件下生长,反映出很强的生态适应能力。

The leaf water potential and biomass of Z. xanthoxylum were investigated by pot experiment under different soil water stress. The results are as follows, the leaf water potential of Z. xanthoxylum during the seeding stage dropped following the decrease of soil water content, its biomass was not restrained under the light and medial water stress but was remarkably reduced under the severe water stress（P〈0.05）. Distributive proportion of biomass in the individuals varied regularly with the decrease of soil water content. It has alse been revealed that the ratio of the root to crown of Z. xanthoxylum increased in the whole individuals,the proportion of the stems by contrast with the leaves on the overground,the proportion of the yellow leaves by contrast with the green leaves decreased,and the ratio of the roots with diameter〈2 mm to the roots with diameter〉2 mm in underground increased. These results showed the adaptive ability of Z. xanthoxylum to aridity by the adjustment of itself.