GLDH超表达水稻愈伤组织的耐盐性研究

为了探讨内源抗坏血酸(ascorbic acid，AsA)水平对水稻愈伤组织耐盐性的影响，以AsA合成关键酶半乳糖内酯脱氢酶(L-galactono-1,4-lactone dehydrogenase, GLDH)基因超表达型水稻(GO)为材料，研究了盐胁迫(1% NaCl)下GO愈伤组织继代生长及相关抗性生理指标的动态变化。结果表明，盐胁迫下GO愈伤组织生长明显优于野生型(wild type，WT)，表现为生长速率较快，愈伤颗粒较大，致密，呈浅黄色。盐胁迫下GO愈伤组织中还原型AsA与总AsA含量不断下降，DHA含量总体上也呈下降趋势，但其氧化还原势(AsA/DHA)在胁迫初期上升，后期快速下降。进一步研究发现盐胁迫下GO愈伤组织中MDA含量先上升后快速下降，但其含量显著低于WT，而POD活性在胁迫初期略有降低，在后期又快速升高，其活性总体上显著高于对照。因此上述研究表明GLDH超表达水稻愈伤组织的耐盐性增强与其AsA含量提高有关。

Study on Salt Tolerance of Callus in Rice with GLDH Gene Overexpressing

In order to explore the effect of endogenous ascorbic acid levels on salt tolerance of callus in Rice, dynamic changes of some resistance physiological index and growth of callus in transgenic rice (Oryza sativa L.) for L-galactono-1,4-lactone dehydrogenase (GLDH, EC 1.3.2.3) overexpressing (GO) under salt stress induced by 1% NaCl were studied. The results showed that growth of GO callus was significantly better than WT, such as faster growth rate, larger and looser callus particles, pale yellow. Further research found reduced AsA and total AsA content of GO callus decreased, the content of DHA in general also declined, while its redox potential ( AsA/DHA ratio) first increased, late rapid declined under salt stress, while their contents were always higher than WT. MDA content of GO callus increased first and then decreased rapidly, and its content was significantly lower than that of WT. In addition, POD activity of GO callus slightly decreased slightly in early, and late rapid increased, but its activity was always higher than that of WT. So these results suggest that enhancement of salt tolerance in GO callus is related to increasement of AsA content.