‘改良白凤’桃果实发育过程中糖分及代谢酶活性的变化

Sugars and the activities of related metabolic enzymes in development of ‘kairyo hakuho' peach fruit

以水蜜桃品种‘改良白凤’为试材,测定了果实发育过程中可溶性固形物含量、总糖含量、各糖组分(蔗糖、葡萄糖、果糖和山梨醇)含量及相关代谢酶(酸性转化酶(AI)、中性转化酶(NI)、蔗糖合成酶(SS)、蔗糖磷酸合成酶(SPS)及山梨醇氧化酶(SOX))的活性,并对糖分与相关酶活性进行了相关性分析。结果表明:葡萄糖与果糖在盛花后30 d含量最高,蔗糖在盛花后110 d含量最高,且为果实中糖的主要积累形式;SS合成方向酶(SS–SD)活性随果实发育不断增加,在果实成熟时活性达到最高,为19.0μmol/(h·g);SS分解方向酶(SS–CD)活性在果实发育初期活性最高,之后迅速下降,在末期活性有所增强;AI和NI在果实发育初期活性最强,之后一直维持在较低水平;在整个发育过程中,蔗糖与SS–SD呈显著正相关,与AI和NI呈显著负相关,与SPS不相关;葡萄糖、果糖与AI、NI、SOX呈显著正相关。综合分析结果:在‘改良白凤’水蜜桃发育过程中,SS–SD是调控蔗糖积累的关键酶,而SPS并不是调控蔗糖代谢的关键酶,AI、NI和SOX在葡萄糖和果糖积累过程中起重要的促进作用。

The content of soluble solids, total sugar,sucrose, glucose, fructose and sorbitol and the activities of sucrose-metabolizing enzymes including acid invertae（AI）, neutral invertse（NI）, sucrose synthase（SS）, sucrose phosphate synthase（SPS） and sorbitol oxidase（SOX） were investigated during the fruit development of cultivars ‘Kairyo Hakuho’, and the correlations between sugar accumulation and the activities of enzymes were further analyzed. Results showed that the content of glucose and fructose was the highest at the 30 th after full blossom, while the sucrose was the main accumulation form of sugar and its content reached the highest at the 110 th after full blossom. SS activity in the direction of synthesizing increased with fruit development and reached the highest at maturity with a rate of 19.0 μmol/（h·g）. SS activity in the direction of breaking down was the highest at the early fruit development, then declined rapidly and enhanced a little at the late fruit development. The activity of AI and NI at the early fruit development was the highest, and then it declined and maintained at a low level. Sucrose was significantly positive correlation with SS-SD, and negative correlation with AI and NI, but there was no correlation between sucrose and SPS. Glucose and fructose was significantly positive correlation with AI, NI and SOX. Therefore, SS-SD was a key enzyme in sucrose accumulation, but SPS was not. AI and NI played an important role in glucose and fructose accumulation.