干旱及复水条件下转基因甘薯抗氧化防御系统特性

以转铜锌超氧化物歧化酶(Cu/ZnSOD)和抗坏血酸过氧化物酶(APX)基因甘薯(TS)及未转基因甘薯(NT)为实验材料,研究在旱后复水条件下转基因甘薯及未转基因甘薯抗氧化防御系统变化。结果显示,连续36h胁迫条件下,TS和NT的SOD活性都先降低后升高,但TS的SOD活性始终高于NT。胁迫至24h时,TS的SOD活性约为NT的1.2倍,复水后二者SOD活性都下降。持续胁迫时,TS的APX活性先升高后降低,NT与之相反,复水后TS和NT的APX活性都是先升高后降低,复水12h,TS的APX活性是NT1.5倍。在水分胁迫条件下,TS抗氧化物质AsA、CAR增长速度较快,复水后,TS中的AsA含量仍显著高于NT水分胁迫条件下TS的膜质受伤害程度要轻于NT,胁迫24h,复水12h,NT的MDA含量均约为TS的1.2倍。实验结果表明,同时转入SOD、APX抗氧化基因后,在胁迫及复水条件下转基因甘薯的抗氧化系统可以更好的对植株体进行保护及修复。

Antioxidative System Characteristics of Sweet Potato Transferred both Cu/Zn Superoxide Dismutase and Ascorbate Peroxidase Gene under Water Stress and Rewatering

Two strains, Cu/Zn SOD and APX gene transferred sweet potato (TS) and non-transgenic sweet potato(Ipomoea batatas L.)(NT),were used as experimental materials to study the effects of Water stress and rewatering on antioxidative system characteristics of sweet potatoes. The result showed that the activities of SOD of both TS and NT first increased and then decreased under water stress, but the activity of SOD of TS was always higher than that of NT, under 24h water stress, the activity of SOD of TS was 20% higher than that of NT. The activities of SOD of TS and NT both decreased after rewatering. Under water stress, the activity of APX of TS firstly increased and then decreased; in NT it firstly decreased and then increased. After rewatering, the activity of APX of both TS and NT firstly increased and then decreased, after12h rewatering, the activity of APX of TS was 50% higher than it of NT (Fig.1). When PEG treatments were imposed for 24h and 36h in TS, the AsA content increased by 12% and 53%, however, the AsA content was in NT increased firstly and then decreased. After PEG treatments for 0h, 12h and 24h, AsA content in TS was higher by 3 %, 18 % and 37 %, than that in NT (p<0.05), respectively (figure 2). Recovery by no PEG solution, AsA content decreased in both TS and NT. Recover for 12h, 24h, AsA content in TS was 45% and 37% higher than that in NT (p<0.05). Under the no stress and PEG treatments for 12h and 24h, CAR content in NT was higher by15 %,21% and 13 %, than that in TS (p<0.05), respectively. After PEG treatments for 36h, CAR content in TS and NT was almost the same. Recovery in on PEG solution, CAR contents decreased in TS and NT. Recovered for 12h, CAR content in NT was 11% higher than in TS Under water stress, the membrane structural stability of TS was better than it of NT, after 24h water stress and 12h rewatering, the MDA content of NT were 20% more than it of TS (Fig.5). The result showed that Transferred both Cu/Zn SOD and APX gene,the antioxidative system of the transgenic sweet potato had a higher ability to protect and recover the antioxidative system of the plant.