4树种主要生理指标对模拟水分胁迫的响应

比较了白毛锦鸡儿、荒漠锦鸡儿、驼绒藜和霸王的主要生理指标叶片含水量、自然饱和亏、超氧化物歧化酶（SOD）活性、可溶性糖和丙二醛（MDA）含量,在不同生长期（夏季和秋季）对不同浓度聚乙二醇（PEG=10%、20%、30%）及不同胁迫时间（0 h、12 h、24 h）模拟水分胁迫的响应差异。结果表明：①霸王、驼绒藜抗干旱损伤的能力总体比两种锦鸡儿强;②同样处理水平下，种间SOD活性差异不显著，各指标夏秋响应差异显著，秋季较夏季敏感，树种抗旱能力与生长期及生理状态有密切的关系;③相关性分析表明,水分胁迫后水分亏缺大的树种，质膜受伤重，SOD保护酶与可溶性糖对树种抵抗水分胁迫起到一定的保护作用，调节协同机制及响应时间存在差异。

Responses of Main Physiological Indexes of Four Tree Species to Simulating Water Stress

Comparison study has been conducted on the response of main physiological indices such as leaf water content, water saturation deficit, SOD activitiy, content of soluble sugar and MDA in plants of Caragana licentiana, Caragana roborovskyi, Ceratoides latens and Zygothyllum xanthoxylum to simulating water stress during different growth period (summer and autumn) under treatments of three PEG concentration(10%, 20% and 30%), and three duration(0 h, 12 h, 24 h). The results are as follows: ① In general, Zygothyllum xanthoxylum and Ceratoides latens are more drought-resistant than Caragana licentiana and Caragana roborovskyi. ② There are not significant difference among SOD activites in defferent species under same treatment. The response of these physiological indices to simulating water stress differ in summer and autumn significantly, more sensitive in autumn that in summer. The ability of species drough-resistance is closely related to their physiological status and growth period. ③ Correlation analysis showed that higher water deficit results more serious membrane harm. SOD activity and content of soluble sugar play a certain protection on species under water stress, but both mechanism of cooperative regulation and time of response are different.