棒叶落地生根叶片中抗坏血酸-谷胱甘肽循环对干旱与复水的响应

Responses of Ascorbic Acid-Glutathione Cycle in Kalanchoe Tubiflora(Harv.)Rays.Hamet Leaves to Drought and Rewatering

棒叶落地生根植株干旱20d与70d,并对干旱70d的植株进行复水处理,测定叶片中抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)与脱氢抗坏血酸还原酶(DHAR)的活性,以及抗坏血酸(AsA)与谷胱甘肽(GSH)含量的变化。结果表明,随着干旱进行,APX与DHAR活性均显著增加,GR活性先增加后降低;AsA、脱氢抗坏血酸(DHA)含量与AsA/DHA比值均显著增加,GSH含量增加但不显著,氧化型谷胱甘肽(GSSG)含量显著增加,GSH/GSSG比值增加但不显著。复水后叶片中APX、DHAR活性显著低于干旱70d时,GR活性高于干旱70d时;AsA、DHA含量与AsA/DHA比值显著低于干旱70d时,GSH、GSSG含量与GSH/GSSG比值低于干旱70d时,但差异不显著。可见,在棒叶落地生根遭遇干旱时,AsA-GSH循环系统清除活性氧的能力提高。

The plants of Kalanchoe tubiflora were treated by drought for 20 or 70 d and some ol them were rewatered after 70 d drought. After treatment the activities of ascorbic acid peroxidase （APX）, glutathione reductase （GR） and dehydroascorbate reductase （DHAR） and the contents of as- corbic acid （AsA） and glutathione （GSH） in leaves were determined. The results indicated that the activities of APX and DHAR increased with the progress of drought, and GR activities increased first and then decreased. AsA and dehydroascorbic acid （DHA） content and AsA/DHA ration increased significantly with drought. Meanwhile GSH content, oxidized glutathione （GSSG） content, and GSH/GSSG ration increased but the increases were not significant. After rewatering, activities of APX and GR decreased significantly compared with that in plants suffered drought for 70 d and GR ac- tivity increased. AsA and DHA content and AsA/DHA ration decreased significantly compared with that in 70 d - drought plants~ the decease of GSH, GssG content and GSH/GSSG ration also found but the differegce was not significant. Therefore, the ability that scavenged ROS by AsA--GSH cycle in K. tubiflora was improved after they suffered drought stress.