不同水分胁迫对绵毛水苏幼苗形态和生理特性的影响

以绵毛水苏幼苗为试材,以正常供水为对照,研究不同水分胁迫(淹水、渍水、中度干旱、重度干旱)对绵毛水苏形态和生理指标的影响。结果表明:(1)绵毛水苏植株在淹水处理3d后外围叶片坏死,根系死亡,但茎基部有不定根萌生;渍水处理植株地上部始终无明显变化,但部分根系根尖变褐色;干旱处理7d时叶片萎蔫,且重度干旱处理叶片萎蔫程度大于中度干旱。胁迫解除后,除淹水处理在第13天恢复生长外,其余处理均在第2天恢复正常生长。(2)绵毛水苏叶片含水量和根系活力在淹水处理下显著降低,在渍水处理下无明显变化;在干旱胁迫下,叶片含水量迅速下降,而根系活力升高。(3)在各水分胁迫条件下,绵毛水苏植株叶、根的相对电导率和MDA含量均较对照显著升高,且根部受损程度均重于叶片,其中淹水胁迫受损最严重。(4)淹水处理叶片可溶性蛋白含量下降,可溶性糖、游离脯氨酸持续积累;渍水和干旱处理叶和根的可溶性糖、可溶性蛋白和游离脯氨酸均升高。研究认为,绵毛水苏具有较强的渗透调节能力,在渍水和干旱胁迫解除后迅速缓解膜质过氧化伤害,恢复正常生长;绵毛水苏虽不能在长时间淹水条件下生长,但可在渍水条件下正常生长,且能忍受干旱胁迫,可应用于滨水消落带等水分变化较大的区域。

Morphology and Physiological Characteristics of Stachys lanata Seedling under Water Stress

Taking the seedlings of Stachys lanata as test materials, and the normal water supply as control, we studied the influence of different water stress(waterflooding, waterlogging, moderate drought and severe drought) on the morphological and physiological indexes. The results showed that: (1) under waterflooding treatment for three days, the leaves gradually necrosis and root died, but adventitious roots germinated at the base of stem. Under waterlogging treatment, there was no obvious change in the above ground state, and there were some brownish root tips in the root system. Leaves wilted under drought treatment for seven days, and the degree of leaf wilting in severe drought treatment was higher than that in moderate drought treatment. After relief, except that waterflooding treatment resumed growth on the 13th day, the other treatments plants returned to normal growth on the second day. (2) The relative water content in leaf and root vitality both decreased under the waterflooding, but no significant changes were found in waterlogging, while the former decreased rapidly and the latter increased in drought treatment. (3) Under the conditions of water stress, the relative conductance and MDA content in leaf and root were both significantly higher than that of the control. The damage of the root was more serious than that of the leaf, and the damage of waterflooding stress was the most serious. (4) Under the waterflooding treatment, the contents of soluble protein decreased, soluble sugar and free proline accumulated continuously with the extension of stress time, the content of soluble sugar, soluble protein and free proline in leaf and root under waterlogging and drought treatment all increased. It can be seen that S. lanata had strong osmotic adjustment ability. After the release of waterlogging and drought stress, the damage of membrane peroxidation was alleviated rapidly and then return to normal growth. Although S. lanata could not lived under waterflooding for long time, but could normally growth under waterlogging, while had a good tolerance to drought stress. So, it could be used in the regions where the water content changes greatly in the waterfront drop zone and so on.