罗伯逊脐橙在不同生境下果实有机酸代谢相关酶的研究

以罗伯逊脐橙为试材,研究了四川3个生态型区5个代表性园片中的果实有机酸代谢相关酶的活性,以及它们的变化动态与果实有机酸积累关系,旨在探讨引起不同生境下果实有机酸含量差异的主要酶。结果表明,PEPC和CS是影响果实有机酸合成的重要酶,而影响有机酸分解的重要酶则是IDH;在不同生境下,果实整个生长发育过程中CS、MDH和线粒体ACO活性差异不明显,而IDH活性的差异则达到极显著水平,然而花后120d后,果实内PEPC和细胞质ACO活性差异极显著,说明IDH才是引起不同生境下脐橙果实有机酸含量差异的主要酶,而PEPC和细胞质ACO则起一定作用。

Study on the organic acid-metabolizing enzymes in Robertson Navel orange fruit collected from different habitats

Experiment was conducted with fruit of Robertson Navel orange cultivar collected from 5 representative orchards located in 3 ecotype areas in Sichuan province for studying the organic acid accumulation and their related enzymes during the fruit development process, especially on the changes in activities of citrate synthase (CS), phosphoenolpyruvatecarboxylase (PEPC), cis-aconitase(ACO), isocitrate dehydrogenase (IDH) and malate dehydrogenase (MDH). The results showed that CS and PEPC played an important role in organic acid accumulation in fruit at the early stage of fruit development,while IDH was the key enzyme that cleaved citrate from 120 days after full bloom to the fruit ripening. During the process of fruit development, the activities of CS,MDH and mitochondrial cis-aconitase in fruit were similar in different habitats, whereas IDH activity changed significantly in different habitats. However, after 120 days after full bloom, the activities of PEPC and cytosolic cis-aconitase also changed significantly. It is suggested that the organic acid concentration in fruit grown in the different habitats was mainly determined by IDH, and partly by PEPC and cytosolic cis-aconitase, but not CS, MDH and mitochondrial cis-aconitase.