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

<正> 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.