This paper is a continuation of our preceding report and describes the effects of ethanol treatment for removal of astringency from the “on-tree” fruit of the Japanese persimmon, cv. Hiratanenashi, from the pre-bloom stage extending to the end of July on the reappearance of astringency and on changes in other fruit character-istics.
Fruit or fruit buds at pre-bloom were enclosed in polyethylene bags containing 5 or 10ml of 5% ethanol until they completely lost their astringency. Then the bags were removed and the fruit was allowed to remain on the tree.
1) Except for the fruit treated in mid- or late July, soluble tannin reappeared in the fruit within one to two weeks after de-bagging with increasing degrees of reappearance in earlier treatments. Fruit treated before mid- or late June displayed astringency throughout the flesh tissue, while those treated later did so only in portions of the flesh tissue near the calyx end.
2) The browning of flesh tissue appeared strongly in the fruit treated at the end of June and later, except for the portion of flesh tissue near the calyx end where astringency reoccurred. In fruit in which astringency reoccurred in all the tissue, only minor and localized browning, if any, was detected at the distal end of the fruit.
3) Fruit shape and size were variously affected by the dates of ethanol treatment. Treatments applied between mid-May and mid-June tended to cause flattening of the fruit. Those treated between late June and mid-July showed reduced fruit diameter and distorted shape, while treatment at the end of July had almost no effect on fruit shape and size.
4) Mitotic activity of flesh tissue was most active from the end of May to early June, and almost ceased in late June and was located mainly in the calyx end of the fruit. Its possible contribution to the reappearance of astringency after ethanol treatment is discussed.