POSSIBLE CAUSE OF ASTRINGENT PEACH FRUIT AND BIOSYNTHESIS OF PEHNOLIC COMPOUNDS

白桃成熟果实总酚含量在不同果园间差异较大，同一果园内不同树种间差异不显著。酚类物质含量与总可溶性固形物含量、果重和树龄无关。总酚含量越大，土壤电导率越高，但总酚含量与土壤pH值的关系不明显。无论果园还是果园，果实总酚含量在果实生长第一阶段末期下降，之后迅速上升，在第二阶段中期达到最大值，第三阶段迅速下降到较低水平。在整个果实生长过程中，总酚含量较高的果园果实高于果实含量较低的果园。酚类物质含量与地上部生长和土壤水分的关系不是…更多的观察者。PAL(L-苯丙氨酸解氨酶)活性在阶段1较高，在阶段2中期达到最大值，之后没有检测到活性。在整个阶段1和阶段2的前半部分，果实中的酚类物质含量越大，PAL活性越高。三岛白桃和金桃果实的总酚含量最高，大久保和白桃次之，川中岛白桃和长白桃的总酚含量很低。在大多数品种中，酚类物质的相对分子质量在阶段1中较大，在阶段2中较低，在阶段3中又有所增加。高效液相色谱法分析表明，桃果实中存在6种酚类化合物，与品种无关。阶段1和阶段2中儿茶素含量大于绿原酸，阶段3中儿茶素含量大于绿原酸。较少

The total phenolic contents in the mature 'Hakuto' peach fruits varied widely among the orchards while significant difference among trees in the same orchard was not observed. Phenolic content ded not correlate with the contents of tatal solublee solids, fruit weight, and tree age. The larger the total phenolic contents, the higher was the EC of soil, but the relationship between total phenolic contents and soil pH was not observed.Regardless of orchard, phenolic contents in fruit decreased towards the end of Stage 1 of fruit growth, after which it increased rapidly and reached a maximum in the middle of Stage 2. Phenolic contents rapidly decreased to a lower level during Stage 3. Throughout fruit growth, total phenolic contents were larger in the fruits from orchard which phenolic content in the mature fruits was high than in the fruits from orchard which it was low, especially during Stage 2. The relationships between phenolic contents and the shoot growth and soil moisture were not … More observed. PAL (L-phenylalanine ammonialyase) activity was high during Stage 1 and reached a maximum in the middle of Stage 2, after which no activity detected. Throughout Stage 1 and the first half of Stage 2, the larger the phenolic contents, the higher was the PAL activitiy in fruit. However, no relationship was observed between the PAL activity and the contents of N, Mn, Cu and B which have been related to phenolic metabolism.Total phenolic contents in the mature fruits were the highest in Mishima-hakuto and Golden Peach, followed in Okubo and Hakuto, while it was very low in Kawanakashima-hakuto and nectalin. In almost cultivars, molecular weight of phenolics was large in Stage 1 and was low in Stage 2, after which it increased again during Stage 3. The HPLC analysis showed that six phenolic compounds were present in peach fruit irrespective of cultivar. Content of catechin was larger than in that of chlorogenic acid during Stage 1 and 2, while in stage 3 latter was larger than in the former. Less