干旱-复水对两种石斛属植物叶水势的影响

吕朝燕 高智席 严羽 王利霞 魏英 叶丽 卢珊珊 张琴

摘要：石斛属植物多附着在其他植物体或岩石上，水分获取困难，其特殊的水分利用策略是其生存和发展的重要保证。为弄清石斛属植物对干旱胁迫的适应能力和机制，该文选用3年生金钗石斛和铁皮石斛，通过盆栽控水进行干旱胁迫和复水处理，探讨在不同干旱历时和干旱后复水条件下两种石斛的叶水势变化情况。结果表明：随着干旱时间的延长，两种石斛叶水势均呈升高趋势;金钗石斛叶水势由充分供水时的（-1.04±0.02） MPa增加到干旱60 d时的（-0.86±0.03）MPa，铁皮石斛叶水势由（-1.04±0.02） MPa增加到（-0.87±0.03 ） MPa;两种石斛均表现出高水势延迟脱水的抗旱适应机制;干旱结束后复水，两种石斛的叶水势随着复水时间的增加均呈下降趋势;复水20 d时，金钗石斛和铁皮石斛叶水势分别为（-0.96±0.05） MPa和（-0.96±0.02） MPa，其叶水势均未恢复到干旱前充分供水时的水平;相关分析结果显示，两种石斛的土壤含水率和叶水势间相关关系显著（P<0.05）。由此认为，两种石斛属植物均表现出较强的干旱胁迫耐受能力和相对较差的胁迫后恢复能力。

关键词： 金钗石斛， 铁皮石斛， 水势， 干旱胁迫， 复水

中图分类号：Q945

文献标识码：A

文章编号：10003142（2021）02017706

Abstract：Dendrobium plants are attached to other plants or rocks， and water is difficult to obtain. Its special water use strategy is an important guarantee for its survival and development. In order to clarify the adaptability and mechanism of Dendrobium plants to drought stress， threeyearold D. nobile and D. officinale were selected， and the drought stress and rewatering treatment were carried out by potted water control， and leaf water potential changes of the two Dendrobium species were studied under different drought durations and rewatering conditons. The results were as follows： With the prolongation of drought time， the leaf water potential of the two Dendrobium species were increased; The leaf water potential of D. nobile increased from （-1.04±0.02） MPa at the time of full water supply to （-0.86±0.03） MPa at 60 d of drought， and the leaf water potential of D. officinale increased from （-1.04±0.02）MPa to （-0.87±0.03） MPa; The two Dendrobium species showed the droughttolerant adaptation mechanism of highwater potential delayed dehydration; Rewatering after the end of drought， the leaf water potential of the two Dendrobium species showed a downward trend with the increase of rewatering time; After rewatering for20 d， the leaf water potentials of D. nobile and D. officinale were （-0.96±0.05） MPa and （-0.96±0.02） MPa， respectively， and did not return to the level of sufficient water supply before drought; Correlation analysis showed significant correlation between soil moisture content and leaf water potential （P<0.05）. In summary， both Dendrobium plants showed strong drought stress tolerance ability and relatively poor poststress recovery ability.

Key words： Dendrobium nobile， Dendrobium officinale， water potential， drought stress， rewatering

水勢可以直接反映植物水分生理状态，受土壤、植被和大气条件等因素的综合影响，是衡量植物抗旱能力的重要生理指标之一，在土壤-植物-大气循环系统（简称 SPAC）水分运移过程中发挥极其重要的关键作用（Choné et al.，2001）。在水资源匮乏的情况下，水势常被作为判定植物水分亏缺程度的敏感指标。一般情况下，植物组织水势越低，吸水能力越强;反之，水势越高，吸水能力越弱，因此可以确定植物的受旱程度和耐受能力（黄子琛和沈渭寿，2000）。……