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以‘嘎拉’苹果为试材,研究了采后果实后熟软化过程中可溶性糖和淀粉含量、相关酶活性及关键酶基因表达的变化,分析了低温、乙烯因子(1-MCP、乙烯利)处理对它们的影响,探讨了糖和淀粉代谢与采后‘嘎拉’果实软化的关系。结果表明:‘嘎拉’果实软化的初始阶段,淀粉降解对果实软化的影响最显著,并伴随淀粉酶(AM)活性和MdAM基因表达的快速上升,且淀粉含量、AM活性及它们与硬度的相关性均显著受到低温和乙烯因子的调节,表明淀粉降解与‘嘎拉’果实软化关系密切。糖代谢中,蔗糖、果糖和葡萄糖含量变化与果实软化表现显著的相关性,均受到低温和乙烯因子的调节,但仅有蔗糖磷酸合成酶(SPS)活性与果实硬度的变化显著相关。随着果实软化SPS活性和MdSPS基因的表达量不断增加,并显著受乙烯利的促进,受低温与1-MCP的抑制,其活性及其与硬度间的相关性也受到同样的影响,表明蔗糖代谢参与了‘嘎拉’果实的后熟软化,SPS在蔗糖代谢中起重要作用。
The ’Gala’ apple was used as experimental material to study the changes of soluble sugar and starch content, the activity of related enzymes and the expression of key enzyme genes during the ripening and softening of postharvest fruits. The effects of low temperature, ethylene (1-MCP, ethephon ) To deal with their impact on the sugar and starch metabolism and postharvest ’Gala’ fruit softening relationship. The results showed that the starch degradation had the most significant effect on the fruit softening during the initial stage of ’Gala’ softening, accompanied by the rapid increase in amylase (AM) activity and MdAM gene expression, and the starch content, AM activity and their relationship with hardness Correlations were significantly affected by low temperature and ethylene regulation, indicating that starch degradation is closely related to ’Gala’ fruit softening. Sugar metabolism, sucrose, fructose and glucose content and fruit softening showed significant correlation, are subject to low temperature and ethylene factor regulation, but only sucrose phosphate synthase (SPS) activity and fruit firmness changes were significantly correlated. With the increase of fruit softening SPS activity and MdSPS gene expression, and significantly promoted by ethephon, inhibited by low temperature and 1-MCP, its activity and its correlation with the hardness are also affected, indicating that sucrose Metabolism is involved in the late ripening of ’Gala’ fruit, and SPS plays an important role in sucrose metabolism.