Abstract: The O₂^- production rate and H₂O₂ content and the activities of the antioxidant enzymes in the ovule of seedless grape ‘Youngle’and seeded grape ‘Jingxiu’were studied in the different periods after bloom. The results indicated that the concentrations of O₂^- rose all the time, and the increasing rate in the ovule of seedless cultivar ‘Youngle’was greater than that in the ovule of seeded cultivar ‘Jingxiu’during middle and later periods of development; H₂O₂ concentration increased initially and decreased before it increased again. The subsequent increase in the seedless cultivar ‘Youngle’was significantly greater than seeded cultivar‘Jingxiu’. The activities of SOD, CAT and AsA-POD increased initially and dropped drastically after ovule abortion in the seedless cultivar‘Youngle’. But it maintained high level in seeded cultivar‘Jingxiu’. The activity of POD in the ovule of the seedless cultivar ‘Youngle’displayed a similar trend to the other enzymes, but the activity in seeded cultivar‘Jingxiu’ increased constantly, but the increasing speed was lower in later stages. The changes of reactive oxygen content and the activity of antioxidant enzymes in ovules have some relevance to ovule abortion in the seedless cultivar 'Youngle'.

Key words: Grapevine, Seedless grape, Ovule, Deveplopment, Reactive oxygen species, Metabolism