Changes Of Flesh Structure In Harvested Apples And Effects Of 1-MCP On Those Changes

The major apple cultivars grown in Shaanxi province, Such as'Gala'(Malus domestica Borkh. cv.'Gala'),'Red delicious'(Malus domestica Borkh c.v.'Red delicious'),'QinGuan'(Malus domestica c.v.'QinGuan'),'Fuji'(Malus domestica Borkh c.v.'Fuji') and'PinkLady'(Malus domestica c.v.'PinkLady') apples, were chosen to observe the changes in flesh cell microstructure ,ultrastructure and firmness,as well as the effects of 1-MCP on those changes during storage at room temperature. The relationship between flesh cell structure and the apple storeability and the anatomic reason why 1-MCP delayed fruit softening were investigated. The main results were as show:(1) Different apple varieties had different flesh cell structure which had certain influences on its storage life. Apples with such flesh cell shapes as elliptical, polygon, shuttle,and with tight cell arrangement and highly cells over lapping had higher flesh firmness and longer storage life. These characteristics of flesh cell structure could be used as the index in apple breeding program.(2) The enlargement of flesh intercellular space was an important reason for flesh softening during storage. While intercellular spaces were getting bigger and bigger, flesh firmness dropped fast.(3) A series of change in flesh cell structure were observed during the storage, such as cell tensity losing, dilating and wrinkling of cell wall, vanishing of the middle lamella, disorganizing of the fiber, cytoplasm dissolving gradually, plasma membrane invaginating and separating from cell wall, as well as mitochondrion, plastid and vacuole dissolving gradually.(4) Dissolving of middle lamella was the most obvious change of cell wall during the storage, integrity of the middle lamella had considerable influence on flesh firmness. Flesh firmness decreased as the middle lamella was dissolved gradually.(5) 1-MCP treatments maintained the integrity of flesh cell structure to a certain extent. The flesh firmness of treated fruit dropped down slower than that of untreated fruit, therefore, the fruit softening was delayed and the storage quality was improved.