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以野生型(WT)和转正义叶绿体单脱氢抗坏血酸还原酶基因(LeMDAR)番茄为试材,探讨了UV-B胁迫下过表达LeMDAR对番茄抗氧化能力的影响。测定了不同时间UV-B处理下番茄抗坏血酸(AsA)含量,脱氢抗坏血酸(DHA)含量,单脱氢抗坏血酸还原酶(MDAR)活性,光合速率和叶绿素荧光参数等。在UV-B处理下,转基因番茄植株的AsA含量、MDAR酶及抗坏血酸过氧化物酶(APX)活性、H2O2和超氧阴离子清除速率、净光合速率(P n)高于野生型番茄。此外,紫外胁迫下,转基因株系丙二醛(MDA)含量和相对电导率(REC)较野生型增加的少。上述结果表明,MDAR对抗坏血酸再生具有重要作用,过表达LeMDAR提高了番茄植株抗氧化能力,对光合机构有保护作用。
The effect of UV-B stress on the anti-oxidative capacity of tomato was studied by using the wild-type (WT) and transgenic tomato chloroplast LeMDAR gene as test materials. The contents of AsA, DHA, MDAR, photosynthetic rate and chlorophyll fluorescence parameters of tomato under UV-B treatment were measured. Under UV-B treatment, AsA content, MDAR enzyme activity and APX activity, H2O2 and superoxide anion scavenging rate and net photosynthetic rate (Pn) of transgenic tomato plants were higher than wild-type tomato. In addition, the MDA content and relative electrical conductivity (REC) of the transgenic lines increased less under UV stress than that of the wild type. The above results show that MDAR plays an important role in the regeneration of ascorbic acid. Overexpression of LeMDAR enhances the antioxidant capacity of tomato plants and protects the photosynthetic apparatus.