| "Dang Shan" pears in which has not only high nutritional and medicinal value, but also high economic value, the cultivation area and yield of pear in our country present having a rising trend in recent years. However, the process of physical decayed quickly after harvesting and storing in natural conditions or cellars, and the organization structure is easy to damage and infect by pathogenic microorganism. The quality of "Dang Shan" pears drops quickly. So it was of great significance to research and develop the advanced fresh-keeping technology of "Dang Shan" pears.1-MCP could inhibit ethylene-induced physiological and biochemical reactions by competing for ethylene receptor, then cut off the feedback regulation of biosynthesis, and prolonged the storage life of fruits.In this thesis,"Dang Shan" pears were used as the raw materials, studying the fresh-keeping effect of "Dang Shan" pears stored in room temperature and2℃temperature after treated by different concentrations (CK,0.5uL/L,0.75uL/L,1.OuL/L) of1-MCP, and finding the best concentration of1-MCP for storage. Studying on TSS content, total sugar content, titratable acid content, Vc content, hardness, colour, the rate of ethylene production, respiration rate, weight loss and good fruit rate and the activities of PG, POD, SOD and LOX of "Dang Shan" pears. Preliminary discussed the ripening and senescence physiological mechanism of "Dang Shan" pears treated by1-MCP in order to provide the new fresh-keeping theoretical for the application of1-MCP in "Dang Shan" pears.The results of study showed that:1. Under room temperature and2℃temperature, the respiration peak of "Dang Shan" pears were respectively appeared in30d and90d, so it belonged to the respiration climacteric fruit.1-MCP treatment reduced the respiratory rate and inhibited ethylene release rate, postponed the fruit respiration peak and ethylene peak respectively10d and30d. Under room temperature and low temperature, the respiratory peak and ethylene peak were efficiently controlled by the treatment of0.5uL/L,72%,77%,and61.8%,67%lower than CK respectively. Low temperature significantly reduced respiratory intensity and ethylene release rate.2. As the extending of storage time, the total sugar and soluble solids content of "Dang Shan" pears were increased and then decreased, Vc content, total acid content and hardness of "Dang Shan" pears were decreased.0.5uL/L,0.75uL/L,1.0uL/L1-MCP treatment could delay the loss of firmness content, TSS content and total sugar content, retard the decrease of titratable acid and Vc content, inhibit the fruit color change, delay the speed of turning the fruit to the green, maintain the higher water content; The treatment of0.5uL/L1-MCP was more advantageous to the fruit storage and low temperature storage was more advantageous to keep the fruit quality.3. Under room temperature and2℃temperature,1-MCP reduced PG activity, inhibited the fruit softening and maintained the fruit of high hardness, the peak of PG activity was lowest treated by0.5uL/L1-MCP, respectively74.1%and72.3%lower than CK. LOX activity and POD activity, SOD activity respectively remained low and high level in the late storage, and played an important role in remained the integrity of membrane system and fruit hardness, which could delay the maturation and senescence of fruit.4.0.5uL/L,0.75uL/L and1.0uL/L1-MCP could delay the maturation and senescence of fruit. The appropriate concentration of1-MCP treatment was0.5uL/L,25℃,18h, maintained good quality and physiology of "Dang Shan" pears. |
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