六个牡丹品种对干旱胁迫的生理响应机制及抗性评价

以"胡红""姚黄""洛阳红""银红巧对""雨后风光""金岛"6个牡丹品种为试材,研究了干旱条件对牡丹叶内渗透调节物质、丙二醛(MDA)、超氧阴离子O₂^-·含量和抗氧化酶活性变化等生理机制的影响,并利用隶属函数法进行了综合抗性评价,以期探求干旱胁迫下,牡丹叶内渗透调节物质和抗氧化系统对干旱胁迫的调节机制,并利用这些抗性指标评价品种间的抗性关系。结果表明:随干旱程度的增加6种牡丹叶内脯氨酸、可溶性蛋白质、MDA、O₂^-·含量及超氧化物歧化酶(SOD)活性逐渐升高;可溶性糖含量先降后升;过氧化物酶(POD)、过氧化氢酶(CAT)活性前期升高后期降低。重度干旱时,"姚黄""胡红"脯氨酸、可溶性蛋白质含量增加幅度最大,"洛阳红""银红巧对""雨后风光""金岛"增幅较小;"胡红""姚黄"叶内MDA、O₂^-·含量较低,受到的伤害轻于其余4个品种。抗坏血酸过氧化物酶(APX)活性变化品种间差异显著,随着胁迫程度增加,"胡红""金岛""姚黄"APX活性逐渐升高,"雨后风光""洛阳红""银红巧对"APX活性先升高后降低。复水后牡丹生理机能恢复,MDA和O₂^-·含量显著降低,干旱胁迫危害有效缓解。经隶属函数法综合评价,耐旱能力由强到弱顺序为"胡红">"姚黄">"金岛">"雨后风光">"银红巧对">"洛阳红"。

Physiological Response Mechanism and Resistance Evaluation of Six Peony Varieties to Drought Stress

Taking six peony varieties(‘Huhong’‘Yaohuang’‘Luoyanghong’‘Yinhongqiaodui’‘Yuhoufengguang’‘Jindao’) as test materials.The physiological response mechanism of osmoregulation substance,MDA,O₂^-·content and antioxidant enzyme activity in leaves under drought was studied,and the comprehensive resistance evaluation was carried out by membership function method.In order to explore the regulation mechanism of osmotic adjustment substances and antioxidant system in tree peony leaves under drought stress,and evaluate the resistance relationship among varieties by using these resistance indexes.The results showed that the content of proline,soluble protein,MDA,O₂^-·and the activity of SOD in the leaves of six peonies increased with the increase of drought degree.Soluble sugar content first decreased and then increased.The activity of POD and CAT increased in the early stage and decreased in the later stage.In severe drought,the content of proline and soluble protein in ‘Yaohuang’‘Huhong’ increased the most,‘Luoyanghong’‘Yinhongqiaodui’‘Yuhoufengguang’‘Jindao’ had a smaller increase.The contents of MDA and O₂^-· in the leaves of ‘Huhong’ and ‘Yaohuang’ were lower,and the damage was lighter than the other four varieties.The APX activity of ‘Huhong’‘Jindao’‘Yaohuang’ increased gradually with the increase of stress degree,while that of ‘Yuhoufengguang’‘Luoyang hong’‘Yinhongqiaodui’ increased first and then decreased.After rehydration,the physiological function of peony was restored,the content of MDA and O₂^-· were significantly reduced,and the damage of drought stress was effectively alleviated.According to the comprehensive evaluation of subordinate function method,the order of drought tolerance ability from strong to weak was ‘Huhong’‘Yaohuang’‘Jindao’‘Yuhoufengguang’‘Yinhongqiaodui’‘Luoyanghong’.It could be seen that under drought stress,peony could effectively enhance its osmotic regulation function,reduce the damage of drought stress through its own antioxidant mechanism.These resistance indexes could be used to evaluate the resistance relationship among varieties.