外源糖对苹果果实山梨醇代谢相关酶活性的影响

以新红星苹果为试材,采用果实圆片孵育体系研究了外源糖对SDH和SOX活性的影响。结果表明:在整个发育过程中,苹果果实的SDH活性与葡萄糖、果糖和蔗糖含量间不存在显著的相关性;而SOX活性与葡萄糖和果糖含量间存在极显著的相关性。外源山梨醇和蔗糖均可提高发育前期和发育后期苹果果实的SDH和SOX活性,其中以山梨醇的诱导作用最为显著。外源葡萄糖对SDH活性的增加具有显著的促进作用,但抑制SOX活性,而外源果糖对苹果果实SDH和SOX活性的诱导效果与葡萄糖恰好相反。结果还表明,外源糖对发育前期苹果果实SDH和SOX的诱导作用均显著高于对发育后期苹果果实的诱导作用。由此推断,苹果果实中山梨醇代谢相关酶的活性变化受到可溶性糖的调控。

Effects of Soluble Sugars on Related Enzyme Activities of Sorbitol Metabolism in Developing Apple Fruit

The regulating effects of soluble sugars on activities of SDH and SOX were studied in ＇ Starkrimson＇ apple fruits through disk incubation. The results showed that the activities of SDH in apple fruit had no significant correlation with the concentrations of glucose, fructose and sucrose during the whole developmental period. However, the activities of SOX had significant positive corre- lation with glucose and fructose concentrations. The results also indicated that exogenous sorbitol and sucrose highly increased the activities of SDH and SOX, moreover, the exogenous glucose indicated the highest promoting effects on SDH activity, but inhibited the activity of SOX significantly. On the other hand, the exogenous fructose showed reverse regulating action on SDH and SOX ac- tivities compared with exogenous glucose. The exogenous study also indicated that the regulating effects of exogenous sugars on the fruit at early developmental stage were much higher compared with the fruit at late developmental stage. It is concluded that the metabolism of sorbitol in apple fruit was regulated by soluble sugars.