水杨酸对水分胁迫黄瓜幼苗叶片生理过程的影响

研究了外源水杨酸 salicylic acid,SA 对水分胁迫下黄瓜幼苗叶片主要生理过程的影响 . 1m mol/L 的 SA处理黄瓜幼苗 2 4 h后 ,叶片中 POD活性剧增 ,SOD活性增加不明显 ,H2 O2 清除酶 CAT和 APX活性受抑制 ,H2 O2 含量上升引起膜脂过氧化产物 MDA含量上升 ,造成轻度氧化胁迫 ;在随后水分胁迫过程中 ,经 SA预处理积累的 H2 O2 诱导 APX和 CAT活性上升并清除产生的 H2 O2 ;SA预处理后 ,叶片中 Rubisco含量及其基因转录水平明显高于对照 ,光合作用受影响较小 .这表明 SA使黄瓜幼苗生理活性有较大改善 ,增强了植株对水分胁迫的抗性

Effects of salicylic acid on leaves of cucumber seedlings under water stress

The effects of exogenous salicylic acid (SA) treatment on important physiological processes in leaves of cucumber seedlings under water stress were studied. After 24 hours treatment with 1 mmol/L SA, activity of POD increased dramatically. Activity of SOD didn't increase conspicuously. Activities of CAT and APX, which are H_2O_2 removing enzymes, have been restricted. Increasing of H_2O_2 content results in the increasing of MDA (production of oxidation on membrane), and caused slight oxidation stress. In the subsequently progress of treatments, H_2O_2 accumulated after the pretreatment with SA made the activity of CAT and APX increase. H_2O_2 was eliminated then. Content and gene transcrip level of Rubisco in seedlings pretreated by SA was evidently higher than control. The influence of water stress on photosynthesis declined. This progress improved the physiological functions of the seedlings pretreated by SA in compared with the seedlings of control, and increased the endurance of cucumber seedlings in drought stress.