Organic Acid Concentrations and the Relative Enzymatic Changes During the Development of the Citrus Fruits

Abstract

Seasonal changes in enzyme activities and citrate concentration during the development of citrus fruits were investigated. The result showed that the organic acid concentrations reached a peak in the 100-130 days after anthesis and gradually declined during later stages of fruit maturation in most varieties of citrus, but declined only slightly thereafter in lemon [Citrus limon (L.) Burm]; there is no relation between the activity of citrate synthetase (CS) and the different acid concentration in different citrus fruits; the increase of the activity of the cytosolic aconitase in the late period of the development of citrus fruits accelerated the degradation of citric acid in citrus fruits; the higher the activity of phosphoenolpyruvate carboxylase (PEPC) and the ratio of NAD-dependent isocitrate hydrogenase (PEPC/NAD-IDH), the more the concentrations of organic acids in citrus fruit.