甜瓜果实发育过程中糖积累与蔗糖代谢相关酶的关系

以伊丽莎白和乌引1号2个厚皮甜瓜品种为试材,测定了不同发育时期果实中的糖、淀粉含量以及蔗糖代谢相关酶—酸性转化酶(AI)、中性转化酶(NI)、蔗糖磷酸合成酶(SPS)和蔗糖合成酶(SS)的活性变化等,并对甜瓜果实糖积累的生理机制进行了系统分析。结果表明:(1)2个品种果实中糖积累动态十分相似,即成熟期之前,糖积累缓慢,特别是蔗糖几乎很少积累;进入成熟期,果实中蔗糖迅速积累,而单糖略有下降。(2)AI、NI的活性变化对2种甜瓜果实中糖的积累和构成具有重要影响,SS对2种甜瓜果实中糖积累的作用较小,SPS活性升高与成熟期伊丽莎白果实中蔗糖的积累相一致。(3)果实中糖的积累与淀粉含量变化无明显关系。

Study on the Correlation of Sugar Accumulation and Sucrose-metabolizing Enzymes During the Developing Period of Muskmelon(Cucumis melon)

The content of sucrose, glucose, fructose, starch and the activities of sucrose-metabolizing enzymes, including acid invertase(AI), neutral invertase(NI), sucrose synthase (SS) and sucrose phosphate synthase(SPS), were studied in sarcocarp of Elizabeth and Wuyin No.1 muskmelon varieties. Physiological mechanism of sugar accumulation in muskmelon fruit was systemically analyzed. The results showed that sugar accumulation was very slow in Elizabeth and Wuyin No.1 fruit before ripe stage, especially for sucrose. Sucrose accumulated sharply during ripe stage, while the content of fructose and glucose reduced slightly. Accumulation and components of sugars were affected evidently by AI and NI in muskmelon fruit, but the action of SS was weak. Sucrose accumulation accorded with the increase of SPS activity in sarcocarp of Elizabeth during ripe stage. Otherwise, there was no obvious correlation between sugar accumulation and starch conversion.