桃果实和叶片中糖分的季节变化及其与碳代谢酶活性的关系研究

以晚熟的艳丰一号桃为试材,研究了果实和叶片中可溶性糖、淀粉及相关酶活性的变化。结果表明,在果实生长发育早期,果实和叶片中的可溶性糖主要是还原糖,中后期,还原糖维持在相对较低的水平上,非还原糖大量积累;在整个果实生长发育期间,果实中蔗糖、葡萄糖、果糖含量显著地高于叶片,而叶片中山梨醇和淀粉含量则显著地高于果实;叶片中蔗糖、葡萄糖、果糖含量和果实中山梨醇含量较稳定,在整个生长季节中差异较小;在整个生长发育期间蔗糖在果实中持续积累,尤其是在成熟前急剧增加,果实内葡萄糖和果糖含量在生长发育前期总体呈下降趋势,中后期维持在一个相对较低的水平上;叶片中山梨醇含量在生长前期下降,之后维持在相对稳定状态。在整个果实生长发育期间果实中果糖含量与NI、SS和SDH活性及葡萄糖含量与SS和SDH活性呈显著正相关;叶片中葡萄糖含量与SDH活性呈显著正相关且果糖含量与SS和ADPGPPase活性呈显著负相关,此外叶片中蔗糖含量与SPS活性呈显著正相关,但果实中蔗糖含量与SPS不存在任何相关性。因此认为各主要糖的合成与转化在叶片和果实中可能存在着不同的酶调控机制。

Seasonal Changes in Carbohydrate Content and Related Enzyme Activity in Fruit and Leaves of‘Yanfengyihao’ Peach Variety

Seasonal changes in carbohydrate and starch content and related enzyme activity in fruit and leaves of Yanfengyihao peach variety were studied. Results showed that the most soluble sugars in fruit and leaves have been reducing during the early fruit development stage while non-reducing sugars accumulated; the reducing sugar maintained in a low level during mid and late stage of fruit development. The content of sucrose, glucose and fructose were significantly higher in fruit than those in leaves during the whole period of fruit development, however, sorbitol and starch content remained in significantly lower level in fruit than in leaves. The content of sucrose, glucose and glucose in leaves and sorbitol in fruit kept a stable level during fruit development. Sucrose content in fruit increased from the beginning to the end of fruit development and the content of glucose and fructose tended to decrease in fruit during early stage of fruit development and remained in a low level thereafter. Seasonal evolution of sorbitol content in leaves decreased firstly, and then kept a low stable level. A significantly positive correlation was found between fructose content and activity of NI,SS and SDH,and between glucose content and SS and SDH activities in fruit; however, a significantly positive correlation between glucose content and SDH activity and negative correlation between fructose content and activity of SS and ADPGPPase in leaves. Moreover, the content of sucrose was negatively correlative with the activity of SPS in leaves and no any correlation was found between the content of sucrose and SPS in fruit. It is suggested that the enzyme system regulating the synthesis and catabolism of carbohydrate in fruit may be different from those in leaf.