果実•野菜の成熟生理と貯蔵に関する研究 (第2報)

Abstract

The changes in respiration rates, ethylene production, internal ethylene concen trations and flesh firmness were investigated during the maturation and ripening periods of pear fruits, using 3 species and several cultivars, as follows: Pyrus communis L. var. sativa DC. (Bartlett, La France and Winter Nelis), Pyrus serotina Rehd. var. culta (Yakumo, Nijisseiki, Niitaka and Kikusui), Pyrus ussuriensis Maxim. var. sinesis Kikuchi (Ya-li, Rai-Yan-Tsu-li and Auto-li). The fruits were picked 2-3 times at different stages of maturity and stored at 20°C.1. Three cultivars of P.communis, Bartlett, La France, and Winter Nelis showed a typical climacteric pattern of respiration. Respiration and ethylene production in both La France and Winter Nelis were much lower than in Bartlett.2. Among P.serotina, Yakumo and Kikusui fruits picked at two different stages of maturity showed a rise in respiration; respiration didn′t rise in Nijisseiki and Niitaka fruits picked at commercial harvest maturity, but did in fruits picked at the immature stage. Ethylene production in Yakumo increased with rising respiration, but the other 3 cultivars maintained a very low level of production during the experimental period.In Nijisseiki, exogenous ethylene treatment caused a rise in respiration immedi ately after picking. This effect continued only in the presence of exogenous ethylene, and could be reproduced in the same fruit when re-treated with ethylene after a month of storage.It was concluded that Yakumo and Kikusui can be classified as climacteric fruits, while Nijisseiki and Niitaka are non-climacteric fruits.3. Three cultivars of P.ussuriensis; Ya-li, Rai-Yan-Tsu-li and Auto-li showed a typical climacteric accompanying a rise in ethylene production.