关键词: 脐橙, 品种, 有机酸积累, 代谢相关酶

Abstract: Organic acid accumulation and their related enzymes in orange fruit were studied in Jingyan orchard.Three navel orange varieties were selected with ‘Robertson Navel’ orange, ‘Newhall navel’ orange and ‘Harvest navel’ orange.The activities of citrate synthase(CS), cis-aconitase, phosphoenolpyruvatecarboxylase(PEPC), mito-aconitase, isocitrate dehydrogenase(IDH) and malate dehydrogenase(MDH) were measured.The results showed that the variations of organic acid content in different varieties fruit was mainly determined by organic acid cleavage in mid-and late stage of fruit development.Few differences were observed in the activities of CS, MDH, cis-aconitase, and mito-aconitase of fruit among different varieties orange.However, the activities of IDH and PEPC were significantly varied in different varieties orange from 120 days after full bloom to the fruit ripening, in the different varies.It was suggested that the differences of organic acid content in fruit with different varieties was mainly determined by IDH, and partly by PEPC, but not CS, MDH and mito-aconitase cis-aconitase.Moreover, IDH and PEPC influenced organic acid content in fruit with different varieties by regulating citrate cleavage and the organic acid accumulation during the mid-and late stage of the fruit development, respectively.

Key words: navel orange fruit, varieties, organic acid accumulation, metabolizing enzymes