Soluble sugar contents in fruits and leaves during fruit development and their relationship in peach cultivars of difference in fruit glucose/fructose

Chinese. 研究不同葡萄糖/果糖（glucose/fructose，G/F）类型桃果实内G/F差异的部位和时期。以不同G/F类型的6个桃品种（G/F≈1品种：‘冈山白’、‘山一白桃’和‘燕红’；高G/F品种：‘张黄7号’、‘龙246’和‘临白7号’）为试材，采用高效液相色谱法测定果实发育期果实和叶片中可溶性糖含量，并在盛花后74 d或101 d测定了‘冈山白’、‘山一白桃’、‘张黄 7号’和‘龙 246’新梢韧皮部中可溶性糖的含量。两类不同G/F桃果实中均以蔗糖作为主要碳水化合物积累形式，花后43～85 d蔗糖含量很低，随后持续快速积累直至果实成熟；花后43～85 d山梨醇有升高趋势，在果实成熟前40 d左右迅速降低；葡萄糖和果糖含量在果实发育早期较高，之后逐渐降低；但两类不同G/F桃在整个果实发育过程中G/F值与果实成熟时相似。叶片中贮藏的可溶性糖主要是蔗糖和山梨醇，在果实整个发育期间，G/F≈1品种叶片中G/F约为1～3，而高G/F品种叶片中G/F约为2～7。G/F≈1品种‘冈山白’和‘山一白桃’与高G/F品种‘张黄7号’和‘龙246’韧皮部中山梨醇占总可溶性糖47%～58％，显著高于蔗糖、葡萄糖和果糖的含量，G/F为0.8～0.91，且两类不同G/F桃品种间G/F不存在显著差异。光合产物在韧皮部的运输对桃果实的G/F没有显著影响，果实中G/F的差异主要由于果实内糖代谢差异所导致。

English. Research was aimed to find out when the difference of glucose/fructose (G/F) take place during fruit development in peach cultivars of two G/F types in fruits (G/F≈1 and high G/F) at maturity and if there is an influence of end products in leaves on G/F in fruits. Six peach cultivars were used as materials, which differ in G/F in fruits at maturity (G/F≈1 cultivars: ‘Hakuto’, ‘Shanyibaitao’ and ‘Yanhong’; High G/F cultivars: ‘Zhanghuang 7’, ‘Long 246’ and ‘Linbai 7’). Seasonal changes of soluble sugar contents in fruits and leaves were investigated by high performance liquid chromatography method (HPLC). Moreover, soluble sugar in phloem at 74th day or 101st day after full bloom were measured in ‘Hakuto’, ‘Shanyibaitao’, ‘Zhanghuang 7’ and ‘Long 246’. Sucrose, the main soluble sugar in fruit, was lower at the early stage (43-85 days after full bloom), and accumulated quickly till maturity; Sorbitol content increased from early fruit development stage, and tended to decrease from the beginning of final fruit rapid growth stage (around 40 days before harvest); Glucose and fructose contents were high at the early fruit development stage, then decreased gradually. However, glucose approximately was equal to fructose contents in G/F≈1 cultivars while bigger G/F values were observed for high G/F cultivars throughout fruit development. Sucrose and sorbitol were main soluble sugars in leaves, whereas G/F ranged 1-3 in leaves of G/F≈1 cultivars, and 2-7 in leaves of high G/F cultivars. Sorbitol was remarkably greater than sucrose, glucose and fructose in phloem of both G/F≈1 and high G/F cultivars, accounting for 47%-58% of the total soluble sugars. G/Fs in phloem were 0.8-0.91, and there were no obvious differences between the cultivars of two G/F types. Transportation of the photosynthates through phloem from leaves to fruits showed no obvious effect on G/F in fruits. Different G/F in fruits of the two types of cultivars resulted from different sugar metabolisms in fruits.