为解决嫁接厚皮甜瓜含糖量下降的问题,以自根厚皮甜瓜和嫁接厚皮甜瓜为试材,探讨了不同浓度硝酸钙处理对嫁接厚皮甜瓜糖代谢的影响.结果显示:叶面喷施不同浓度硝酸钙对嫁接厚皮甜瓜果实糖含量的影响程度不同.与嫁接对照相比,0.5％硝酸钙处理显著增加了嫁接厚皮甜瓜果实发育后期(处理后14～42 d)的果糖、葡萄糖、蔗糖含量,降低了棉籽糖和水苏糖含量,提高了肌醇半乳糖含量；0.2％和0.8％硝酸钙处理虽也在一定程度上影响着可溶性糖含量,但影响程度低于0.5％硝酸钙处理；处理21d后,3个浓度的硝酸钙处理均极显著增加了果实中总糖含量,且0.5％硝酸钙处理还极显著增加了淀粉含量；但与自根对照相比,0.5％硝酸钙处理的果糖、葡萄糖、蔗糖、淀粉和总糖含量仍未能增加至自根厚皮甜瓜水平.从果实的蔗糖代谢及半乳糖代谢相关酶来看,与嫁接对照相比,叶面喷施不同浓度的硝酸钙均显著或极显著的增加果实发育中期(处理后14 ～ 28 d)酸性转化酶、碱性α-半乳糖苷酶和果实发育中后期(处理后28～42 d)蔗糖磷酸合成酶的活性,但对于中性转化酶和蔗糖合成酶活性影响不显著；与自根对照相比,0.5％硝酸钙处理的酸性转化酶活性未达到自根对照水平,蔗糖磷酸合成酶活性大幅提升,与自根对照差异不显著.结果表明:与嫁接对照相比,叶面喷施不同浓度硝酸钙均可不同程度提高嫁接厚皮甜瓜果实淀粉、总糖、葡萄糖、果糖、蔗糖含量及其果实发育前中期的酸性转化酶、碱性α-半乳糖苷酶和果实发育中后期的蔗糖磷酸合成酶等糖代谢相关酶活性,其中0.5％硝酸钙处理效果最佳,增加了果实发育中后期蔗糖含量,具有改善嫁接厚皮甜瓜果实品质的作用.%In order to solve the problem of sugar content decrease in grafted muskmelon ( Cucumis melon L.) fruit, the self-rooted and grafted muskmelon were taken as test materials, the effects of different calcium nitrate concentrations on sugar-metabolic enzymes activities in grafted muskmelon fruit were studied. The result indicated that the effects of different nitrate calcium concentrations on sugar contents in the grafted muskmelon fruit were different. Compared with the control, the treatment of 0.5 % nitrate calcium concentration significantly increased the fructose, glucose, sucrose and galactose contents, while significantly decreased the raffinose and stachyose contents in the later part of fruit development ( 14-42 days after treatment). Although the treatment of 0.2 % and 0.8 % nitrate calcium concentrations affect the soluble sugar content to some extent, the affecting degree is lower than the 0.5 % treatment. Three levels of calcium nitrate treatments significantly increased the total fruit sugar content 21 days after treatment, and 0.5 % calcium nitrate treatment also significantly increased the starch content. However, compared with the self-root control, 0.5 % calcium nitrate treatment did not increase the contents of fructose, glucose, sucrose, starch and total sugar to the level of self-rooted muskmelon fruit. In view of fruit sugar metabolism and galactose metabolism enzymes, compared with the grafted control, each level of calcium nitrate treatment has significantly enhanced the acid invertase, alkaline a -galactosidase and sucrose phosphate synthase activities in the mid stage ( 14-28 days after treatment) of fruit development, yet sucrose synthase and neutral invertase activities had no change. Compared with self-rooted control, 0.5 % calcium nitrate treatment could not increase the acid invertase activities to the level of self-root, but the sucrose phosphate synthase activities were improved obviously. The results indicated that different levels of calcium nitrate treatments can enhance starch, total sugar, glucose, fructose and sucrose content in grafted muskmelon fruit, and enhance acid invertase, alkaline a -galactosidase and sucrose phosphate synthase activities. Among them, the effect of 0.5 % concentration calcium nitrate treatment is the best. These results suggested that increasing sucrose content in the mid or later part of fruit development may improve the quality of grafted muskmelon fruit.
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