| 摘要: |
| 【目的】 研究转基因与非转基因甘薯幼苗在水分胁迫不同时间及解除胁迫后，膜脂过氧化及抗氧化防御系统中主要指标的变化情况，深入探讨甘薯的耐旱性及旱后自我修复机制。【方法】 以转基因甘薯(T)与非转基因甘薯(N)幼苗为材料，以150 g/L的PEG模拟干旱条件，探讨水分胁迫不同时间及复水后甘薯叶片生理指标的变化情况。【结果】 （1）水分胁迫12 h，甘薯叶片相对膜透性和MDA含量增加，相对含水量(RWC)、光化学效率（Fv/Fm）下降，抗坏血酸过氧化物酶（APX）、超氧化物歧化酶（SOD）活性显著增加。水分胁迫时间延长至24和48 h，植株受到进一步损害，其中转基因甘薯植株叶片中SOD活性先升后降， APX活性变化则与之相反，而非转基因甘薯植株的SOD、APX活性变化与转基因植株的相反；在同等胁迫条件下，转基因植株叶片抗氧化酶活性的表达均远高于非转基因植株。（2）水分胁迫12 h后复水，转基因和非转基因甘薯植株RWC、相对膜透性、MDA含量等均快速恢复到对照水平；水分胁迫延长至24和48 h后复水，转基因和非转基因甘薯植株叶片相对膜透性、MDA含量均在复水初期升高，而后下降，RWC、Fv/Fm则在复水后持续上升，而抗氧化酶活性的变化略为复杂。水分胁迫24 h后复水，转基因甘薯植株SOD和APX活性均在复水初期下降，然后回升，胁迫48 h后复水，SOD和APX活性则呈先升后降再升高的双峰变化趋势；非转基因植株在水分胁迫24和48 h后复水的表现与转基因植株略有差异，且变化幅度显著低于转基因植株。【结论】 在甘薯体内同时转入Cu/Zn SOD和APX基因，可以有效减轻甘薯在水分胁迫条件下受损害的程度，提高甘薯的抗氧化胁迫能力，在水分胁迫逆境解除后，也可以更快更强地进行自我修复。 |
| 关键词: 水分胁迫 复水 转基因甘薯 抗氧化酶 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金项目(50779063)；国家重点基础研究(973)发展计划项目(2009CBll8604)；西北农林科技大学拔尖人才支持计划项目 |
|
| Recovery effects of transferring both Cu/Zn SOD and APX genes in sweet potato under water stress |
|
LU Yan-yuan,DENG Xi-ping
|
| Abstract: |
| 【Objective】 Response of antioxidative system and lipid peroxidation during water stress and rewatering in transgenic sweet potato (T) both expressing Cu/Zn SOD and APX genes and non-transgenic line (N)，were studied to explore how transferring genes improve the recovery ability of sweet potato.【Method】 Transgenic and non transgenic sweet potatoes were used as experimental material under 150 g/L PEG simulated water stress condition,the physiological changes of sweet potato under different water stress time and rewatering time were discussed.【Result】 (1)After 12 h water stress,membrane permeability and MDA content increased,while RWC and Fv/Fm decreased.12 h water stress also improved the expressing of APX and SOD.Longer water stress (24 and 48 h),brought more harm to plants.The activity of SOD in transgenic sweet potato increased first and then declined gradually,APX did the contrary way.The performance of SOD and APX in non transgenic plants showed just the reverse of what the transgenic line did.However,the activity of SOD and APX of T was always higher than that of N under all water stress levels.(2)Rewatering after 12 h water stress,RWC,membrane permeability and MDA content could recover to control level quickly.When recovered from 24 and 48 h water stress,membrane permeability and MDA content in both lines were increased firstly and then declined,and RWC,Fv/Fm kept going up after rewatering.However,the performance of antioxidative enzymes was more complicated.Rewatering after 24 h water stress,the activity of SOD and APX of transgenic plants decreased firstly and then increased significantly and they showed double peak values when plants recovered from 48 h water stress. The activity of antioxidative enzymes of N plants showed a little different trend.However,the change extent in N plants was much lower than that in T plants.【Conclusion】 Overexpressing both Cu/Zn SOD and APX genes in sweet potato leaves can protect them from stress environment and enhance their drought tolerance.Moreover,it also improves their recovery ability during rewatering. |
| Key words: water stress rewatering transgenic sweet potato antioxidative enzyme |
