氯化胆碱对盐胁迫黄瓜幼苗渗透调节物质及活性氧代谢系统的影响

以盐敏感型黄瓜品种津春4号为材料,采用水培方法研究了叶面喷施不同浓度(0.5、1.0和1.5 mmol·L-1)氯化胆碱(CC)对NaCl胁迫(75 mmol·L-1)下黄瓜幼苗鲜重、叶片叶绿素、渗透调节物质含量及活性氧代谢系统的影响.结果表明:(1)单独CC处理可提高黄瓜叶片的叶绿素、可溶性糖和可溶性蛋白含量以及过氧化氢酶(CAT)与过氧化物酶(POD)活性,降低O2·-产生速率,但对植株鲜重及超氧化物岐化酶(SOD)活性影响不大;(2)NaCl胁迫处理增加了黄瓜幼苗叶片中可溶性糖和可溶性蛋白含量,增强了SOD、POD和CAT活性,提高了O2·-产生速率及丙二醛(MDA)的含量,但同时降低了叶绿素含量与植株鲜重;(3)盐胁迫前CC预处理可缓解黄瓜幼苗叶绿素含量和植株鲜重的下降、以及MDA含量和O2·-产生速率的上升趋势,且进一步提高了盐胁迫下黄瓜叶片中SOD、POD和CAT活性.因此,适宜浓度的氯化胆碱可显著提高盐胁迫下黄瓜叶片的抗氧化酶活性,提高清除活性氧的能力,缓解盐胁迫对黄瓜幼苗细胞膜的伤害,增强黄瓜幼苗的耐盐性.

Effects of Choline Chloride on Osmotic Adjustment Substances and Reactive Oxygen Species Metabolism of Cucumber Seedlings under Salt Stress

The experiment was carried out by a salt-sensitive cucumber variety ’Jinchun No.4’ in a hydroponic system to investigate the effects of NaCl stress(75 mmol·L-1) on the plant fresh weight,contents of chlorophyll,soluble sugar and protein,the reactive oxygen species metabolism of seedling leaves and the positive effects of exogenous choline chloride(CC,0.5,1.0,1.5 mmol·L-1) pretreatment.The results indicated that:(1) Compared with the control plants,CC treatment induced the increase of soluble sugar and protein contents,the activities of peroxidase(POD) and catalase(CAT) and the decrease of O-·2 producing rate,and little change in the activity of superoxide dismutase(SOD) and the plant fresh weight.(2)NaCl treatment induced an increase on the contents of soluble sugar and protein,the content of malonaldehyde(MDA),the activities of SOD,CAT and POD,and a decrease on the content of chlorophyll and the plant fresh weight.(3)Activities of SOD,POD and CAT of salt-stressed cucumber leaves were significantly enhanced with the foliar spray of CC;While higher MDA content and O-·2 producing rate,lower chlorophyll content and the plant fresh weight of the salt-stressed cucumber plants were alleviated by the CC pretreatment.It is indicated that foliar spray of CC can mitigate cucumber seedlings’ salt injury and promote itsgrowth by increasing activities of protective enzymes,protecting the integrity of membrane.