枣果实发育过程中有机酸质量分数及相关代谢酶活性的变化

摘要

By method of high performance liquid chromatography(HPLC),the components and mass fraction of organic acids in fruit of Junzao and wild jujube were determined.In the meantime,the activities of organic acid-metabolizing enzymes,such as malate dehydrogenase(NAD-MDH),malic enzyme (NADP-ME),enol phosphate type pyruvate carboxylase(PEPC),citrate synthase(CS),were analyzed during the development of Junzao and wild jujube fruit.The results showed that:(1) Except for tartaric acid,the mass fraction of both malic acid and citric acid were increased during the early stages of jujube fruits development and decreased at the later stages.(2) The activities of NAD-MDH and CS had the same trend with malic acid and citric acid concentration during the development of jujube fruits.However,the change of NADP-ME activity was on the contrary.(3) Correlation analyses showed that there was a positive correlation between the mass fractions of malic acid and the activities of NAD-MDH,but the correlation between the mass fractions of malic acid and the activities of NADP-ME was negative.The activities of CS showed a significant positive correlation with the mass fractions of citric acid,while there was no same correlation between the activities of PEPC and the mass fractions of malic acid and citric acid.Therefore,this study assumed that NAD-MDH,NADP-ME and CS activities might play significant roles in organic acids biosynthesis and degradation,but the role of PEPC activity was a little.%以骏枣和酸枣为试材,采用高效液相色谱(HPLC)检测了枣果实发育过程中有机酸组分和质量分数,并对苹果酸脱氢酶(NAD-MDH)、苹果酸酶(NADP-ME)、磷酸烯醇式丙酮酸羧化酶(PEPC)、柠檬酸合成酶(CS)等相关代谢酶的活性进行测定.结果表明:(1)骏枣和酸枣果实发育过程中,除酒石酸外,苹果酸和柠檬酸质量分数的变化均呈先升高后降低的趋势.(2)NAD-MDH、CS活性与苹果酸和柠檬酸质量分数的变化趋势基本一致,NADP-ME活性变化则相反.(3)相关性分析表明:NAD-MDH活性变化与苹果酸质量分数呈正相关,NADP-ME活性变化与苹果酸质量分数呈负相关;CS活性变化与柠檬酸质量分数达到极显著正相关;而PEPC活性变化与苹果酸和柠檬酸质量分数相关性不大.因此,NAD-MDH、NADP-ME和CS活性对枣果实中有机酸代谢发挥重要作用,而PEPC作用不大.