干旱胁迫对3种海岛植被修复植物生长与生理指标的影响

Effects of Drought Stress on Morphological and Physiological Characteristics of Three Island Vegetation Restoration Plants

以海岛植被修复典型植物木麻黄(Casuarina equisetifolia)、台湾相思(Acacia confusa)和夹竹桃(Nerium indicum)2年苗为研究对象,在盆栽条件下持续干旱胁迫11周后复水6周,研究3种植物在实验过程中形态和生理生化指标的变化,比较3种植物的耐旱能力,为植被修复现场简易快速判断植物的需水情况提供参考.结果表明:1)3种植物对持续干旱胁迫的响应表观上首先表现为近根端(植株下部或老叶)开始出现少量干枯,随后蔓延到新叶,叶色开始变淡,叶部逐渐失水下垂卷曲,在临近死亡时则出现全株叶干黄、枯萎.2)3种植物的生长状态、叶部含水率、细胞膜透性和丙二醛含量与干旱胁迫程度均呈显著或极显著相关,野外条件下可根据植物的生长状态简易快速地判断植物受干旱胁迫情况,再根据细胞膜透性和丙二醛含量进一步辅助判断植物的需水情况.3)根据生长状态与相关生理生化指标综合判断,3种植物的耐旱性强弱为夹竹桃>台湾相思>木麻黄,分别可耐受11,8和4周的土壤干旱,在干旱缺水地带开展海岛植被修复时,可根据各植物耐旱能力相应延长浇水养护间隔时间,以提高水资源利用率.

To explore effects of drought stress on morphological and physiological characteristics of Casuarina equisetifolia,Acacia confuse and Nerium indicum,which are common used in island vegetation restoration in the southern China,and to compare the drought-resistant capability of the three plants for providing guidance to determine water requirement of plants simply and quickly during island vegetation restoration,these three plants were investigated with 11-week natural drought stress and 6-week re-watering.The results showed that the response of the three plants to persistent drought stress first appeared near the root of the plants(the lower part of the plant or the old leaves)where several leaves withered,then spread to the newer leaves with the color of leaves beginning to fade and the leaves gradually curling,and till closing to death,the whole plant leaves became dry,yellow and withered.Besides,it was found that the growing status,leaf water content,cell membrane permeability and malondialdehyde content of the three plants were significantly correlated with the degree of drought stress,so that the drought stress situation of the plant could be easily and quickly determined according to the growing status of the plant under the field condition,and cell membrane permeability and malondialdehyde content can help to further determinate the water demand of the plant.In addition,the drought-resistant capability of these three species was N.indicum>A.confuse>C.equisetifolia,as according to the growing status,C.equisetifolia,A.confuse and N.indicumcan resist soil drought for 4,8 and 11 weeks,respectively,and the time between watering can be extended according to the drought-resistant capability of plants to improve the water use efficiency.