《植物生理学报》 2021, 57(3): 661-671
以二年生杜仲‘华仲6号’扦插幼苗为试验材料, 研究干旱胁迫及干旱后复水处理下杜仲苗叶片和根系相对电导率、丙二醛(MDA)、渗透调节物质含量及抗氧化酶活性的变化。结果表明: 随干旱胁迫时间的延长, 叶片和根系相对电导率和MDA含量显著升高; 叶片超氧化物歧化酶(SOD)活性无显著变化, 根系的SOD活性呈先降低后升高的趋势; 叶片和根系的过氧化物酶(POD)活性只在胁迫后期显著升高, 叶片过氧化氢酶(CAT)活性先升高后降低, 根系CAT活性只在胁迫后期显著升高; 叶片和根系的脯氨酸含量、可溶性糖含量和可溶性蛋白含量均只在胁迫后期显著升高。复水后, 叶片和根系的相对电导率、 MDA、可溶性糖和可溶性蛋白含量、抗氧化酶活性均有不同程度的下降, 而根系脯氨酸含量显著升高。研究表明,干旱胁迫下, 杜仲叶片依赖POD和CAT活性的增强来保护膜系统, 根系依赖3种酶活性的增强共同保护膜系统, 叶片和根系通过显著积累渗透调节物质维持较高的渗透压抵御干旱胁迫。复水后, 杜仲苗根系的恢复能力较叶片强。
关键词：杜仲; 干旱胁迫; 生理特性; 复水
Corresponding author: DU Hongyan; E-mail: email@example.com
Two-year-old cutting seedlings of Eucommia ulmoides ‘Huazhong 6’ were used to study the changes of relative electrical conductivity, MDA and osmotic adjustment substance contents, and antioxidant enzymes activities in leaves and roots of E. ulmoides seedlings under drought stress and rewatering conditions. The results indicated that with the extension of drought stress time, the relative conductivity and MDA content of leaves and roots increased signifcantly. There was no signifcant change in SOD activity in leaves, but SOD activity in roots decreased frst and then increased. The POD activity in leaves and roots increased signifcantly only in the late stage of stress. And CAT activity in leaves increased frst and then decreased, while CAT activity in roots increased signifcantly only in the late stage of stress. The contents of proline, soluble sugar and soluble protein in leaves and roots increased signifcantly only in the late stage of stress. After rewatering, the relative electrical conductivity, MDA, soluble sugar and protein contents, and antioxidant enzymes activities of leaves and roots decreased to different degrees, while the proline content of roots increased signifcantly. The results showed that under drought stress, the leaves of E. ulmoides depended on the enhancement of POD and CAT activities to protect the membrane system, and the roots relied on the enhancement of three enzyme activities to protect the membrane system together. The leaves and roots maintain a high osmotic pressure to resist drought stress by signifcantly accumulating osmotic adjustment substances. After rewatering conditions, the root system of E. ulmoides seedlings had stronger recovery ability than leaves.
Key words: Eucommia ulmoides; drought stress; physiological characteristics; rewatering
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