甜瓜果实膨大期源库糖分积累及蔗糖代谢相关酶活性调节特征研究

Study on the Regulation Characteristics of Source-sink Sugar Accumulation and Sucrose Metabolism-related Enzyme Activities during Fruit Expansion of Muskmelon

本文以河套蜜瓜为试材,研究了果实膨大期间从源(叶)至库(果实)各部位糖分含量以及蔗糖代谢相关酶活性变化特征,结果显示:蔗糖含量在叶肉、叶茎输导组织、果肉组织中由高到低梯度分布;果糖、葡萄糖含量在果肉组织中最高;淀粉含量在各部位均维持较低水平。蔗糖合成酶(SS)合成方向活性在各部位均最高;蔗糖磷酸合成酶(SPS)活性在各部位均极低;蔗糖转化酶(Ivr)活性在果肉中活性最高且显著高于其他部位。综上所述,甜瓜果实膨大期间SS对糖分积累代谢贡献率最高,与SPS共同作用促进蔗糖的合成与积累,源(叶)中蔗糖的合成与库(果)中蔗糖的降解形成蔗糖浓度梯度,是光合产物由源向库定向运输的重要保证;果实中高活性的Ivr在葡萄糖和果糖的积累过程中发挥重要作用。子蔓叶片蔗糖合成旺盛,生产中加速子蔓叶成熟、防早衰是提高果实产量和品质的重要保证。

Hetao-melon was used as the test material to study the characteristics of the changes in sugar content and the activities of enzymes related to sucrose metabolism from the source(leaves)to the reservoir(fruits)in each site during the fruit expansion period,and the results showed that:the sucrose content was distributed in a gradient of high to low in the leaf pulp,the leaf and stem conductive tissues,and the pulp tissue;the fructose and glucose contents were the highest in the pulp tissue;and the starch content was kept at a relatively low level in all the parts of the site.The activity of sucrose synthase(SS)in the direction of synthesis was the highest in all parts;the activity of sucrose phosphate synthase(SPS)was extremely low in all parts;the activity of invertase(Ivr)was the highest in pulp and was significantly higher than that in other parts.To sum up,SS is the enzyme with the highest contribution rate in the muskmelon fruit expansion period,and it promotes the synthesis and accumulation of sucrose together with SPS.An important guarantee for the directional transport to the sink.The highly active Ivr in the fruit plays an important role in the accumulation of glucose and fructose,so the muskmelon is not a starch-accumulating fruit.The sucrose synthesis of vine leaves is vigorous,and the acceleration of vine leaf maturation and the prevention of premature senescence are important guarantees for improving fruit yield and quality during production.