采后菠萝黑心病发病过程中活性氧的代谢途径

为了探讨采后菠萝黑心病发病过程中活性氧的代谢途径,以‘巴厘’菠萝为材料,将其贮藏在25 ℃条件下,观察黑心病的发病情况,每隔3 d对整果果肉以及健康部位和患病部位的果肉组织进行取样,测定果实发病率以及果肉褐变度,对发病过程中脂氧合酶（LOX）活性和丙二醛（MDA）含量进行了测定,同时对活性氧代谢起关键作用的抗坏血酸（AsA）、谷胱甘肽（GSH）、类黄酮含量以及活性氧清除相关酶（POD、CAT、SOD）活性进行了测定。结果表明,菠萝果实在贮藏第6天开始发病,到15 d时,发病率为100%,褐变度在第6~9天时增长最快;在黑心病发病过程中,与健康部位相比,患病组织伴随着LOX活性的升高,MDA的积累,同时出现AsA的下降、类黄酮含量的显著增加,且患病组织POD、CAT酶活性快速下降,但谷胱甘肽含量和SOD酶活性几乎没有变化。由此可推断,在采后菠萝黑心病发病过程中,AsA、类黄酮、POD、CAT在活性氧代谢中起关键作用。

Metabolism of Reactive Oxygen Species During Development of Black Heart Disease in Post-harvest Pineapple

In order to explore the metabolism pathway of reactive oxygen species (ROS) related to the development of black heart disease in postharvest pineapple, ‘Paris’ pineapple as the material was stored at room temperature and observed for the incidence of black heart disease. The pulp along the equator and the pulp of healthy and diseased parts were sampled separately every 3 days. The incidence of black heart disease and the browning degree of pulp were tested. At the same time, the activities of lipoxygenase (LOX), and the key enzymes of ROS metabolism (POD, CAT, SOD), and the contents of malondialdehyde (MDA), ascorbic acid (AsA), flavonoids and glutathione (GSH) were tested during the course of the storage. The results showed that the black heart disease of pineapple appeared at the 6th day and the incidence rate increased to 100% at the 15th day. From the 6th day to the 9th day, the browning was the fastest. Compared with healthy parts, the diseased tissue was accompanied by increase of LOX activity and MDA accumulation, significant decrease in AsA content and POD, CAT activities, and rapid increase in flavonoid content. The glutathione content and SOD activity did not change significantly. It could be inferred that AsA, flavonoids, POD and CAT play key roles in ROS metabolism during the development of black heart disease in post-harvest pineapple.