Studies on Removability of Astringency and Gultivar Differentiation in Japanese Persimmon.

日本柿品种根据果实在树上脱涩的方式和程度分为4个不同类型。本研究从种子的乙醇产量、花粉和成熟叶片的同工酶谱等方面探讨了涩味的去除与品种分化的关系。种子乙醇产量一般呈双峰曲线，第一个高峰与胚的快速生长期相吻合。但在种子部分之间没有观察到乙醇产量的差异。乙醇脱氢酶（ADH）的活性在种子中也增加了对乙醇生产的发病。授粉恒定类型的层积种子比授粉变异类型的层积种子具有更高的ADH活性。用<12>授粉恒定型和非涩型（PCNA）杂交获得的F_1代果实测定了乙醇产量。具有CV.富玉作为亲本在乙醇产量上表现出很大的差异，而其他亲本则一直生产低乙醇，这表明种子中存在控制乙醇产量的基因。用19个品种的9种花粉同工酶共68条谱带计算相似性指数。PCNA的品种之间有较高的相似性。用葡萄糖磷酸异构酶和苹果酸脱氢酶两种同工酶系统对163个品种中的18个进行了鉴定。但4种果实类型之间的相关性不明显。

Japanese persimmon cultivars are classified into 4 different types depending on the ways or degrees their fruits lose astringency on the tree. This study was undertaken to search for the relationships between removability of astringency and cultivar differentiation in terms of ethanol production by seeds and isozyme patterns of pollen and mature leaves.1). Ethanol production by seeds generally showed 2 peaked curves and the first peak coincided with the rapid growth of embryos. But no difference in ethanol production was observed between seed parts. Alcohol dehydrogenase (ADH) activity in the seed also increased toward the onset of ethanol production. Stratified seeds of pollination constant types tended to show higher ADH activity than pollination-variant ones.2). Ehanol production was determined with fruits of F_<12> progenies obtained from crosses between pollination-constant and nonastringent (PCNA) types. Progenies having cv. Fuyu as a parent showed wide variation in ethanol production while those otherwise constantly produced low ethanol, suggesting the existence of gene(s) governing ethanol production in the seed.3). Similarity indices were calculated using 68 bands obtained from 9 pollen isozymes of 19 cultivars. Higher similarities were found among PCNA cultivars. 18 out of 163 cultivars were identified by combining 2 isozyme systems, glucosephosphate isomerase and malate dehydrogenase, of mature leaves. No relationship, however, was dound among the 4 fruit types.