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为了探讨嫁接增强黄瓜抗冷性的分子机制,以黑籽南瓜为砧木,‘津绿3号’黄瓜为接穗,对低温胁迫下嫁接苗和自嫁苗叶片抗坏血酸—谷胱甘肽循环中抗氧化酶基因的表达和相关酶活性及AsA、GSH和H202含量变化进行了研究。结果表明:低温胁迫下,嫁接苗叶片DHAR mRNA和GR mRNA相对表达量均大于自嫁苗,GalLDH mRNA和APX mRNA相对表达量均与自嫁苗无显著差异;DHAR、GR、GalL-DH和APX活性均高于自嫁苗;AsA和GSH含量与AsA/DHA和GSH/GSSG比值均高于自嫁苗,DHA、GSSG和H2O2含量均低于自嫁苗。嫁接苗叶片DHAR和GR较高的转录水平维持的较高DHAR和GR活性是AsA和GSH含量明显高于自嫁苗的重要原因,而嫁接苗叶片较高的GalLDH和APX活性与GalLDH mRNA和APX mRNA相对表达量无关。
In order to explore the molecular mechanism of grafting to enhance the chilling tolerance of cucumber, taking the black seed pumpkin as the rootstock and the ’Jinlu No.3’ cucumber as the scion, the antioxidation of the ascorbate-glutathione cycle in the grafted seedlings and self-marrying seedlings under low temperature stress Enzyme gene expression and related enzyme activities and AsA, GSH and H202 content changes were studied. The results showed that under low temperature stress, the relative expression levels of DHAR mRNA and GR mRNA in grafted leaves were higher than those in self-marrying seedlings. The relative expression levels of GalLDH mRNA and APX mRNA were not significantly different from those of self-marrying seedlings. DHAR, GR, GalL-DH and APX The activities of AsA and GSH and AsA / DHA and GSH / GSSG were higher than those of self-marrying seedlings. The contents of DHA, GSSG and H2O2 were lower than those of self-marrying seedlings. Higher DHAR and GR activities maintained in grafted seedling leaves at higher transcriptional levels of DHAR and GR are important reasons for higher AsA and GSH contents than grafted seedlings, whereas higher GalLDH and APX activities in grafted seedlings are associated with GalLDH mRNA and APX mRNA relative expression level has nothing to do.