Studies On The Mechanism Of Chilling Injury Of Peaches Stored In Low Temperature

The effects of 1-MCP and CaCl2 at different concentration on respiration rates, the rates of ethylene production, fruit firmness, membrane permeability, the activity of cellulase, PG enzyme related fruit softening and the activity of PPO, POD enzyme associated with fresh browning of 'QinWang'peaches during cold storage were studies in this paper. The mechanism of chilling injury of peaches stored in low temperature and the storage effect of 1-MCP, CaCl2 treatments on peaches were studied all above provided theoretical basis for the mechanism of chilling injury (CI) and measures of control on peaches stored in low temperature .The results of study showed that 'QinWang' peaches was climacteric fruit and had still significant peaks of respiration and ethylene production during cold storage. Fruits treats with 500nL/L 1-MCP markedly inhibited the respiration and hardly appeared climax and the ethylene climax was lower than that of controlled fruits .Fruits treats with 3% CaCl2 treatment also significantly degrade the peak of respiration and ethylene production.In cold storage, fresh firmness hadn't related to 1-MCP and CaCl2 treatment .All fruits including treated and controlled ones remain very higher fresh firmness when cold storage finished. Fruit firmness values indicated the fruits failure to ripen and development of CI occurred. Treatment with 500nL/L 1-MCP or CaCh can markedly inhibited activities related to fruit softening such as cellulase, PG enzyme in cold storage, therefore pectin degrading were inhibited. Relative electric conductivity of skin rapidly increased after 20ds at 0C.It indicated fruits were already injured by low temperature. At the early period of CI incidence, 1-MCP can increase the membrane permeability and the more concentration high, the more effect significant. The treatment of CaCl2 had no apparent effect to decrease fruit relative electric conductivity. Fruits treats with 1-MCP or CaCl2 can't effect soluble solide content of peaches.In the same time of cold storage, the treatment of 500nL/L 1-MCP or 3% CaCl2 all can markedly restrained polyphend oxidase (PPO) and peroxidase(POD) activities when compared with controlled fruits, thus it was efficient to reducing fresh browning and delaying times of browning during cold storage.