不同脐橙品种果实有机酸代谢相关酶的研究

Enzymes Related to Organic Acid-metabolizing in Navel Orange with Different Varieties

研究了四川井研3个脐橙品种果实有机酸代谢相关酶的活性变化动态,及其与果实有机酸积累关系。结果表明:不同脐橙品种果实有机酸含量差异,主要取决于花后120d有机酸分解的量;不同品种间,果实整个生长发育过程中CS、MDH、细胞质ACO和线粒体ACO活性差异不明显;但在花后120d,纽荷尔和丰脐果实内的IDH和PEPC酶活性与罗脐差异显著,而纽荷尔和丰脐果实有机酸与罗脐差异显著,表明IDH才是引起不同脐橙品种果实有机酸含量差异的关键酶,而PEPC则是重要酶,它们分别通过促进果实发育中后期有机酸分解和降低合成来实现品种间有机酸含差异。

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, ＂Ne- whall 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 midand 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 af- ter 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.