Title: Electrolyte Leakage from the discs of Cucurbitaceae Fruits Associated with Chilling Iniury
Abstract: Chilling injury of cucumber fruit (Cucumis sativus L.) of several kinds of cultivars and different stages of maturity, oriental pickling melon (Cucumis melo L. conomon Makino) and winter squash fruit (Cucurbita maxima Duch.) was investi gated to elucidate the relationship between the changes in membrane permeability and the occurrence of chilling injury at low temperature.1. There were considerable deviations in chilling sensitivity among different cultivars of cucumber fruit. In general, the cucumbers of western cultivars showed less sensitivity to chilling than oriental species. Chilling symptom of surface pittings began to appear after storage for five days in the fruit of sensitive cultivars and fifteen days in the fruit of less sensitive cultivars at 5°C.2. Considerable deviations were observed in the chilling sensitivity of different stages of maturity of cucumber fruit cv. Horai, especially, chilling injured pittings occurred only after long term storage period at 0°C in the case of full mature fruit.3. There was a sudden rise of electrolyte leakage from the tissue slices of cucumber, oriental pickling melon and winter squash fruits into deionized water or 0.4 M aqueous solution of mannitol just after the occurrence of chilling injury at 0°C, while electrolyte leakage from the tissue slices of the cucurbits fruits showed no obvious rise throughout storage period at 20°C which was safe temperature.Above-mentioned results suggested that the changes in membrane permeability of the cucurbits fruit tissues during chilling may play an important role in the mechanism of the occurrence of chilling injury of fruits.