Studies On The Changes Of The Physiological Indexes And Enzymes Related To Softening And Senescence Of Dongzao (Ziziphus Jujuba Mill.) Fruit

The experiment was conducted to probe the main physiological indexes and the changes of enzymes, which were related to the softening and senescence with Dongzao pulp, in order to reveal the mechanism of softening and senescence from the aspect of enzyme.1 It was obviously that the characteristic of storage was affected by the different temperature. The fruit can be preserved for about 25 to 30 days only under room temperature, while under cool temperature the period of storage can be prolonged for 65 to 70 days.2 The firmness of fruits descent gradually in the storage of post-harvest. In the former of storage , the firmness descent evenly, and descent steeply in the latter of storage. Cool temperature was helpful to keep the firmness of fruits.3 Water loss of fruit is faint in the former of storage and aggravated in the latter. Water loss was more under room temperature than that under cool temperature. Water loss of half-red fruits was more than that of white-ripe fruit.4 Dongzao belonged to non-climatic fruits. During the course of ripeness, respiration peak was not discovered. Respiration of the fruit can be repressed obviously under cool temperature. Respiration of half-red fruits was more than that of white-ripe fruits under room temperature, but less than that of white-ripe fruits under cool temperature.5 The ethylene production peak of Dongzao had turned up apparently in the course of post-harvest under room temperature, and respiration peak of half-red fruits appeared earlier than that of white-ripe fruits. Moreover, the ethylene quality of half-red fruits is more than that of white-ripe fruits. Production of ethylene suspended, and peak was inevident under cool temperature.6 The change of PG activity was irregular in the former of storage, and only the activity ascent in the latter of storage. PG activity of half-red fruits was more than that of the white-ripe, but the change of its activity was irregular. The change of Cx-cellulase activity was similar to that of PG, and in the former of storage the activity was wavy violently, and in the latter of storage the activity was raised a bit. The change of PME activity was even in the former, and ascent in the latter. PG, PME and Cx-cellulase took...