Distribution and metabolism of ascorbic acid in apple fruits (Malus domestica Borkh cv. Gala)
Distribution and metabolism of ascorbic acid in apple fruits (Malus domestica Borkh cv. Gala)
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DOI：
10.1016/j.plantsci.2008.03.008
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发表时间：
2008-06-01
期刊：
影响因子：
5.2
通讯作者：
Pu, Fei
中科院分区：
文献类型：
--
作者：
Li, Ming-Jun;Ma, Feng-Wang;Pu, Fei
本研究旨在研究抗坏血酸(ASA)在青果和成熟果不同组织中的分布、生物合成和循环。嘎拉苹果(Malus Home Tica Borkh)结果表明，‘嘎拉’苹果果皮的抗坏血酸含量在所有组织类型中最高，这是由较低的抗坏血酸过氧化物酶(APX，EC 1.11.1.11)活性和较高的脱氢抗坏血酸还原酶(DHAR，EC 1.8.5.1)和单脱氢抗坏血酸还原酶(MDHAR，EC 1.6.5.4)活性共同作用的结果。外源饲养表明，瓜皮能够通过L-半乳糖途径和D-半乳糖醛酸途径合成阿司匹林，而果肉和种子只能通过L-半乳糖途径合成阿司匹林。幼果具有较高的抗坏血酸浓度和较强的抗坏血酸合成和循环能力。曝晒的果皮中AsA的含量和对AsA的回收能力均高于遮荫的果皮，而晒面和遮荫的果肉差异不显著。果实维管组织中含有丰富的AsA，表明AsA可以运输到果实维管组织或在‘嘎拉’苹果维管组织中合成AsA。(C)2008爱思唯尔爱尔兰有限公司。保留所有权利。
The objective of this study was to determine ascorbic acid (AsA) distribution, biosynthesis and recycling in different tissues of young and mature fruit of cv. Gala apple (Malus domestica Borkh). Our results showed that the peel of 'Gala' apple had the highest AsA levels among all the tissue types, which resulted from a combination of, lower ascorbate peroxidase (APX, EC 1.11.1.11) activity consuming AsA, and higher dehydroascorbate reductase (DHAR, EC 1.8.5.1) and monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) activities used to recycle AsA. Exogenous feeding of AsA synthesis precursors demonstrated that the peel was capable of de nono AsA biosynthesis via L-galactose and D-galacturonic acid pathways whereas the flesh and seed were only able to synthesize AsA via L-galactose pathway. The young fruit had higher AsA concentration and stronger capability of AsA biosynthesis and recycling. The sun-exposed peel had higher AsA concentration and stronger capability of recycling AsA than the shaded peel, while there was no difference in the flesh between the sun-exposed side and the shaded side. Abundant AsA was found in fruit vascular tissue, which suggests that AsA can be transported to vascular tissues of fruit or vascular tissues could synthesize AsA itself in 'Gala' apple. (C) 2008 Elsevier Ireland Ltd. All rights reserved.