2种甜度差异型甜瓜果实糖分积累及其相关酶代谢特征研究

Sugar Accumulation and Enzymes Metabolic Characteristics of Two Kinds of Muskmelon with Different Sweetness

为研究不同甜度甜瓜果实糖代谢的酶学机制,以具有甜度差异的2种甜瓜‘河套蜜瓜’和‘楼兰王’为试验材料,测定果实发育时期果实糖含量、淀粉含量以及蔗糖代谢相关酶活性变化。结果显示,2种甜瓜果实均呈现单S型动态生长,‘楼兰王’果实膨大期生长速率显著高于‘河套密瓜’。2种甜瓜果实发育期间糖分积累动态基本一致,前期以葡萄糖的积累为主,且‘河套密瓜’葡萄糖积累量显著高于‘楼兰王’;进入转色期后葡萄糖含量下降,蔗糖含量增加,‘河套密瓜’蔗糖含量远高于‘楼兰王’。甜瓜果实糖分积累由蔗糖代谢相关酶协同调控,认为‘河套密瓜’转色期后蔗糖磷酸合成酶和蔗糖合成酶合成方向活性升高,是其蔗糖含量增加的主要原因,成熟期蔗糖磷酸合成酶活性升高是‘楼兰王’果实中蔗糖积累的主要原因。

In order to study the enzymology metabolism in different sweetness melons, the content of sugar,starch and the activities of sucrose-metabolizing enzymes were tested by taking Cucumis melo‘Hetao＇and Cucumis melo‘Loulanwang＇in growth stage as the materials. The results showed that： both of the two varietiespresented a single sigmoid pattern of growth, the growth rate during fruit swelling of‘Loulanwang＇was higherthan that of‘Hetao＇significantly. These two muskmelon varieties had a similar sugar accumulation trendduring fruit development, the glucose accumulation was mainly in early stages, and the glucose accumulationin‘Hetao＇was significantly higher than that in‘Loulanwang＇. In veraison, the glucose content declined andsucrose content increased, the sucrose content of‘Hetao＇was higher than that of‘Loulanwang＇. The sucrose-metabolizing enzymes co- regulated sugar accumulation. After the veraison of‘Hetao＇, the activity of thesynthetic direction of sucrose phosphate synthase and sucrose synthase rose, which could be the major reasonfor sucrose content increase, and the increased activity of sucrose phosphate synthase during the maturationstage was the main reason for sucrose content in the fruit of‘Loulanwang＇.