采后菠萝黑心病发病过程中活性氧的代谢途径
作者:常金梅 何咏 张鲁斌
来源:《热带作物学报》2020年第07期
摘 要: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,對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。
关键词:菠萝;黑心病;活性氧代谢中图分类号:S668.3文献标识码:A
Metabolism of Reactive Oxygen Species During Development of Black Heart Disease in Post-harvest Pineapple
CHANG Jinmei1,2,3, HE Yong1, ZHANG Lubin1,2,3*
1. Lingnan Normal University, Zhanjiang, Guangdong 524091, China; 2. South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences/Key Laboratory of Hainan Province for Postharvest Physiology and Technology of Tropical Horticultural Products, Zhanjiang, Guangdong 524091, China; 3. Jiaying University / Guangdong Provincial Key Laboratory of Conservation and Precision Utilization of Characteristic Agricultural Resources in Mountainous Areas, Meizhou, Guangdong 514000, China
Abstract: 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), flavo
noids 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.
Keywords: pineapple; black heart disease; metabolism of reactive oxygen
DOI: 10.3969/j.issn.1000-2561.2020.07.020
菠萝[Ananas comosus(L.)Merr]是我国南方的特水果,也是我国热区主要经济作物。其种植效益和出口贸易情况直接关系到热区农民的经济收入[1]。采后菠萝主要以鲜果形式在国内市场销售,但采后果实贮藏和运输过程中容易发生黑心病,特别是我国主栽品种‘巴
厘’,其货架期仅为3~5d[2],之后果肉均出现不同程度的褐或黑褐病变,严重影响菠萝产业和进出口贸易发展。菠萝黑心病表现为菠萝外部无任何症状,横剖后果心周围果肉褐变,通常是小果先出现半透明的水渍状或浅褐的小斑点,随着发病程度的加深,褐斑点互相联结成一片,并向果髓发展,最终果髓甚至果肉都变为黑褐[3-5]。严重影响果实的品质,使果实丧失商品价值,对菠萝产业的发展造成极大的危害[6-7]。
正常情况下,植物体内活性氧(ROS)的产生和清除保持动态平衡,植物在受到外界非生物逆境胁迫时,会造成细胞代谢的紊乱,诱导产生过量的ROS,引起细胞的氧化伤害,进而破坏细胞正常结构,致使植物体内的生物膜脂过氧化、DNA受损等多种毒害效应发生,最终导致细胞死亡,植物表现出局部坏死、褐变等症状[8-11]。而植物体内存在一套清除活性氧、防止其毒害的保护体系,包括酶促和非酶促2类防御保护系统,酶促保护系统中的保护酶系主要由超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)等组成;非酶促即是抗氧化物质,主要包括抗坏血酸(AsA)、谷胱甘肽(GSH)、类黄酮等[12-13]。本研究主要针对采后菠萝黑心病发病过程中防御活性氧毒害的保护系统进行了研究,旨在明确黑心病发病过程中起关键作用的活性氧代谢途径,为明确菠萝黑心病发生的生理机制奠定基础。
>reactive oxygen species (ros)
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