岩生植物雅安紫云菜对干旱及复水的生理响应

Physiological Responses of Rock Plant Strobilanthes limprichtii to Drought Stress and Rehydration

选择自然状态下生长在岩石边坡上的岩生植物雅安紫云菜为研究材料,通过人工控制土壤含水量的盆栽试验模拟自然界中的干湿交替现象,对雅安紫云菜中与其抗旱相关的叶绿素含量、膜质过氧化、渗透调节物质及抗氧化酶活性等11个生理生化指标进行了测定和分析,探讨雅安紫云菜对干旱胁迫的适应性及其生理机制。结果显示:(1)在干旱胁迫条件下,雅安紫云菜叶片具有较强的水分保持能力,叶绿素含量减少幅度较小,且复水后叶片相对含水量和叶绿素含量均能迅速恢复。(2)干旱胁迫9d后,叶片中超氧阴离子含量、过氧化氢含量以及丙二醛含量持续增加,同时抗氧化酶SOD和POD活性显著升高,而其叶片电解质外渗率、渗透调节物质可溶性糖含量和脯氨酸含量在干旱胁迫12d后开始大幅增加,复水后这些指标都恢复到接近对照水平。(3)在持续21d的干旱胁迫后,土壤含水量降低到4.26%,雅安紫云菜植株叶片呈现严重萎蔫,植株倒伏,但是复水后植株仍能较快恢复正常生长。研究表明,雅安紫云菜具有较强的渗透调节能力、酶促抗氧化活力以及叶片保水能力,从而表现出较强抗干旱能力,并且在恢复水分供应后能迅速恢复植物生长势,可以作为西南地区岩石边坡绿化的潜力景观植物。

Strobilanthes limprichtii is a rock plant naturally growing on the stones of dry valley in the southwest part regions of China,and this plant is found to be very tolerant to drought stress and infertile soil in its natural habitat.Elucidating the physiological responses to drought stress and the following rehydration will help us understand the physiological mechanism and adaption of this plant species to drought resistance.In the present study,we measured the phenotypic and physiological responses,including content of chlorophyll,lipid peroxidation,osmosis-regulating substances,and activities of antioxidant enzymes after drought stress through withholding water and rehydration treatment.The results showed that：（1）the relative water content（RWC）and content of chlorophyll modestly declined under drought stress,while the RWCand the content of chlorophyll rapidly increased after rehydration.（2）Progress drought stress treatment after 9days,the contents of malondialdehyde（MDA）,superoxide radicals（O-·2）,and hy-drogen peroxide（H2O2）,and the activities of superoxide dismutase（SOD）and peroxidase（POD）increased,while the level of the electrolyte leakage,and the contents of soluble sugar and proline increased after 12 days drought stress treatment.With rehydration,the contents of MDA,O-·2,and H2O2 quickly and activities the SOD and POD,the contents of soluble sugar and proline gradually decreased.（3）After21days progressive drought stress treatment,the soil water content decreased to 4.26%,and the leaves is severely wilted with the flattened plant,but rehydration recovered the plant growth progressively.These above results indicated that S.limprichtii has the relative potent capacity on the osmotic adjustment,enzymatic antioxidation,and leaf water holding,and it was conclude that this plant has the great capability to cope with drought stress and can recover from rehydration quickly.Therefore,S.limprichtii could be used as a potential landscape plant for the side-slope greening.