干旱胁迫对三种观赏草叶片渗透调节的影响

Effect of Drought Stress on Osmotic Adjustment in the Leaves of Three Ornamental Grasses

用盆栽控水的方法研究干旱胁迫对三种观赏草渗透调节的影响,以探讨其抗旱的生理机制。结果表明:三种观赏草的渗透调节能力都随胁迫而发生变化,其中抗旱性最弱的弯叶画眉草,随着胁迫时间的延长渗调能力降低;抗旱性最强的蒲苇渗调能力在胁迫早期变化较小,但随着胁迫时间的延长,渗调能力持续增大;抗旱性中等的狼尾草的渗调能力在干旱胁迫期间高于蒲苇,但随着胁迫程度的加剧和胁迫时间的延长,其渗调能力下降,复水后渗调能力降低幅度最大。三种观赏草积累的有机渗调物质有所不同。K+、Na+、Ca2+、Mg2+均参与了观赏草的渗透调节,K+、Ca2+是其主要的渗调离子,K+含量最大,Ca2+增幅最大。

The effect of drought stress on osmotic adjustment ability in the leaves of the ornamental grasses was studied with pot experiment in order to uncover the physiological mechanisms for drought tolerance.The results showed that the osmotic adjustment ability of the three ornamental grasses changed after drought stress treatment.The osmotic adjustment ability of the drought sensitive variety Curvedleaf Indian Lovegrass decreased gradually.In contrast,the osmotic adjustment ability of strong drought-resistant variety Selloa Pampasgrass changed slightly at early stage and significantly increased with the extension of the drought stress treatment.The osmotic adjustment ability of moderate drought-resistant variety Chinese Pennisetum was higher than that of Selloa Pampasgrass during drought stress,however decreased when the drought stress level and duration were increased.Furthermore,its osmotic adjustment ability decreased more than the others after rewatering.The main osmotic regulation substances were different among the three grass species.The inorganic ions such as K^＋,Na^＋,Ca^2＋,Mg^2＋ were involved in osmotic adjustment of ornamental grass,but K^＋ and Ca^2＋ played major role.