In the experiment, the recoverability of the sweet potato , which expressed both Cu /Zn superoxidedis- mutase (SOD ) and ascorbate peroxidase (APX) in chloroplasts , was compared with its control plants , and foliar applica- tion of exogenous hydrogen peroxide (H2O2) before drought stress on enhancement of seedling recovery capability after drought stress was studied . The transgenic sweet potato and its non-transgenic control plants were treated with 10% PEG and pretreated with 1.0 mmol/L H2Q2 before drought stress , antruxidative enzymes system , content of MDA and H2O2 and photosynthetic rate of each plant were tested in this experiment . Under water stress and a short time after re-watering , for transgenic sweet potatothe , activities of the three mentioned anti-oxidative enzymes and photosynthetic rate were higher and the content of MDA and H2O2 were lower compared with the non-treatments ; At the terminal of re-watering , the recovery capabilities of the anti-oxidative enzymes were stronger , the content of MDA and H2O2 was lower, and pho- tosynthetic rate was higher . It was also observed that in the recovery process of the plants treated with 1.0 mmol/L H2O2 before drought stress , compared with the non-treatments, anti-oxidative enzymes was stronger , and the content of MDA and H2O2 was higher, while the photosynthetic rate was lower . A stronger droughtnesistant ability and a stronger recovery capability after stress was showed in transgenic sweet potato compared with non-transgenic sweet potato under the treat- ment of drought stress . However, the pretreatment with 1.0 mmol/L H2O2 enhanced stress level.%对转入铜/锌超氧化物歧化酶(Cu/Zn SOD)和抗坏血酸氧化酶(APX)基因的甘薯和非转基因甘薯进行PEG胁迫处理(PE组)和H2O2处理后再胁迫处理(PE+组),对比胁迫后两个处理组及其对照组的抗氧化酶活性、MDA与H2O2的变化情况.得出胁迫和复水前期,转基因植株抗氧化酶活性和光合速率高于非转基因植株,MDA和H2O2含量则低于非转基因植株,复水后期抗氧化酶活性下降较快,出现较高的光合速率以及较低的MDA和H2O2含量;PE+组比PE组表现出了较强的抗氧化酶活性,也出现较高的MDA和H2O2含量和较低光合速率.研究表明:转基因甘薯更具有抗旱优势;H2O2预处理后有加重其胁迫程度的趋势.
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