Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas, Apartado 13034, E-50080 Zaragoza, Spain.
J Exp Bot. 2010;61(1):87-97. doi: 10.1093/jxb/erp285.
In plant cells, antioxidants keep reactive oxygen species at low concentrations, avoiding oxidative damage while allowing them to play crucial functions in signal transduction. However, little is known about the role of antioxidants during fruit maturation, especially in legumes. Snap pea (Pisum sativum) plants, which have edible fruits, were grown under nodulating and non-nodulating conditions. Fruits were classified in three maturity stages and antioxidants were determined in the seeds and seedless pods. Maturation or prolonged storage of fruits at 25 degrees C led to a decline in antioxidant activities and metabolites and in gamma-glutamylcysteine synthetase protein. Notable exceptions were superoxide dismutase activity and glutathione peroxidase protein, which increased in one or both of these processes. During maturation, cytosolic peroxiredoxin decreased in seeds but increased in pods, and ascorbate oxidase activity was largely reduced in seeds. In stored fruits, ascorbate oxidase activity was nearly abolished in seeds but doubled in pods. It is concluded that symbiotic nitrogen fixation is as effective as nitrogen fertilization in maintaining the antioxidant capacity of pea fruits and that, contrary to climacteric fruits, a general decrease in antioxidants during maturation does not involve oxidative stress. Results underscore the importance of the antioxidant system in reproductive organs and point to ascorbate-glutathione metabolism and cytosolic peroxiredoxin as key players in pea fruit development.
在植物细胞中，抗氧化剂将活性氧维持在低浓度，避免氧化损伤，同时允许它们在信号转导中发挥关键作用。然而，关于抗氧化剂在果实成熟过程中的作用，特别是在豆科植物中，人们知之甚少。豌豆（Pisum sativum）植物具有可食用的果实，在结瘤和不结瘤的条件下生长。果实分为三个成熟阶段，在种子和无籽豆荚中测定抗氧化剂。在 25 度下成熟或延长果实贮藏时间会导致抗氧化剂活性和代谢物以及γ-谷氨酰半胱氨酸合成酶蛋白的下降。值得注意的例外是超氧化物歧化酶活性和谷胱甘肽过氧化物酶蛋白，这两种酶在一个或两个过程中都增加了。在成熟过程中，种子中的细胞质过氧化物酶减少，但在豆荚中增加，而抗坏血酸氧化酶活性在种子中大大降低。在贮藏的果实中，抗坏血酸氧化酶活性在种子中几乎被废除，但在豆荚中增加了一倍。因此，共生固氮与氮施肥一样有效，能维持豌豆果实的抗氧化能力，与呼吸跃变型果实不同，在成熟过程中抗氧化剂的普遍减少不涉及氧化应激。结果强调了抗氧化系统在生殖器官中的重要性，并指出抗坏血酸-谷胱甘肽代谢和细胞质过氧化物酶作为豌豆果实发育的关键因素。
