脂氧合酶与番茄采后成熟的关系

采后番茄果实组织的脂氧合酶（ＬＯＸ）活性随成熟衰老期的进程而改变，从绿熟期（ＭＧ）到转红期（Ｔ）ＬＯＸ酶的活性逐渐增高，然后降低，其模式呈现跃变型果实的特点。利用外源乙烯分别处理绿熟期、发白期和转红期的果实，其ＬＯＸ酶的活性较对照都有明显提高。用ＬＯＸ酶处理番茄果实组织，乙烯产量没有明显提高，然而电导率有大幅度增加，二羟基萘（ＤＨＮ）能部分抑制ＬＯＸ酶的这一作用。ＬＯＸ酶的活性增加需要有果蔬体内乙

Effects of Lipoxygenase on the Postharvest Physiology of Tomato Fruit

The activity of lipoxygenase was measured in fruit percarp slices of tomatofruit (Lycopersicon esculentum Mill. cv. Zhongshu 4) at different stages of ripening. Theactivity of lipoxygenase was found to increase gradually from mature green stage to turningstage then to decline from pink stage to red stage. The activity became undetectable at theover ripe stage. When lipoxygenase was added to the fruit tissue slices, there was no significant increase in ethylene production, but the conductivity of the incubation medium increased, which was reversed by adding DHN (1, 5-dihydroxy-napthalene), an inhibitor of lipoxygenase in the incubation medium. When intact fruits were treated withethylene, lipoxygenase activity increased significantly. The paper concludes that the increase in lipoxygenase activity requires the biosynthesis of endogenous ethylene or the application of exogenous ethylene. The possible role of lipoxygenase in fruit ripening was alsodiscussed.