| Based on the standard starch-iodine test guide made by Chris and general maturity indices, a new starch test guide for judging the maturity of 'Gala', 'Qinguan'and 'Fuji'apples main grown in Shaanxi province were developed; The effects of 300nL?L-1 and 600nL·L-1 1-methylcyclopropene (1-MCP) on the respiration, ethylene production, fruit quality and protein patterns in 'Gala'apple were studied during the storage at 0℃and within the subsequent 7-day shelf life at room temperature. The physiological and biochemical mechanism of ripening of apples treated with 1-MCP were also probed. The potential application of lower concentration of 1-MCP to apple storage was discussed. The main results acquired were as follows: (1) Firmness, total soluble solids and titratable acids in 'Gala', 'Qinguan'and 'Fuji'apples during maturing were linearly correlated with harvest date, which can be used as reference for determining the harvest date of these cultivars. The starch index of 'Gala', 'Qinguan'and 'Fuji'apples increased significantly during maturity, which can be used as the reliable index in determining the maturity and harvest date for these cultivars. Referring to the starch test guide developed in this experiment, 'Gala', 'Qinguan'and 'Fuji'apple should be harvested when the starch index reached 5, 7 and 8 respectively, when they reached the horticultural maturity. This guide can be extended in determining the maturity and the harvest date of these cultivars. (2) 300nL·L-1 1-MCP significantly inhibited the respiration and ethylene (C2H4) production, slowed down the decrease in the flesh firmness and titratable acids of 'Gala'apples during storage, but had no effect on the total soluble solids. No significant difference was found between 300nL·L-1 and 600nL·L-1 of 1-MCP in 'Gala'apple. To reduce the cost of 1-MCP, 300nL·L-1 1-MCP can be used in 'Gala'apple commercial storage. (3) SDS-PAGE analysis indicated that five differential protein bands appeared during 120-day storage at 0 ℃in non-treated fruits, both 300nL·L-1 and 600nL·L-1 1-MCP treatment delayed or inhibited the appearance of those proteins. |
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