果梅果实发育过程中有机酸含量及相关代谢酶活性的变化特征

摘要

以优选荔波野生梅单株'荔波-3'和'荔波-11'为试验材料,采用高效液相色谱法(HPLC)测定了果梅果实在发育过程中有机酸含量及相关代谢酶活性变化特征.结果表明:(1)'荔波-3'和'荔波-11'果梅果实中柠檬酸和苹果酸主要在果实发育后期积累,花后140 d两品种的柠檬酸积累量达到最大,且果实中总酸的积累量也相应的达到最大值.(2)柠檬酸积累量与柠檬酸合成酶(CS)活性呈极显著正相关关系,'荔波-11'因CS活性高于'荔波-3',使得其果实成熟时的柠檬酸含量高于后者.(3)苹果酸积累量与磷酸烯醇式丙酮酸羧化酶(PEPC)和NAD-苹果酸脱氢酶(NAD-MDH)活性呈极显著正相关关系,但与NADP-苹果酸酶(NADP-ME)活性呈负相关关系;在花后45~100 d内,果梅果实中PEPC和NAD-MDH活性迅速升高,而NADP-ME活性相对较低,使苹果酸积累量迅速增加;在花后120~140 d,'荔波-3'果实中PEPC、NADP-MDH活性显著高于'荔波-11',而其NADP-ME活性低于'荔波-11',导致成熟时'荔波-11'的苹果酸含量高于'荔波-3'.可见,果梅果实的有机酸主要在果实发育后期积累,有机酸积累差异受多个酶协同调控;苹果酸的积累差异主要由NAD-MDH、PEPC和NADP-ME活性协同变化引起,柠檬酸积累差异主要受CS活性变化影响.%Taking the optimizing plant 'Libo-3'and 'Libo-11'Prunusmume which was native to Guizhou Province as materials,using the method of ultra performance liquid chromatograph (UPLC),we measured the changes of organic acid contents and relative metabolic enzyme activities during the development of Prunusmume fruit.The results showed that:(1)citric acid and malic acid of'Libo-3'and'Libo-11'main-ly accumulated in the late period of fruit development,after anthesis the accumulation of citric acid reached the maximum at 140 d,the amount of total acid in the fruit also accordingly reached the maximum value. (2)The accumulation of citric acid was related to the activity of citrate synthase (CS),the content of citric acid of 'Libo-11 'was higher than that of 'Libo-3 'since for its CS activity was higher at the ripening stage.(3 )The content of malic acid exhibited positive correlation with the activities of PEPC and NAD-MDH,while the NADP-ME activity exhibited negative correlation.The difference in malic acid accumula-tion is mainly caused by the coordination change of PEPC,NAD-MDH and NADP-ME activities.After an-thesis 45 to 100 d ,the activities of PEPC and NAD-MDH increased rapidly,while the NADP-ME activity was relatively low,promoting the massive accumulation of mailc acid.After anthesis 120 to 140 d,PEPC and NAD-MDH activities of 'Libo-3 'was significantly higher than the activities of 'Libo-11 ',while NADP-ME activity of 'Libo-11 'was lower.As a result,the content of malic acid of 'Libo-11 'is higher when mature.The late period of fruit development is a critical period for the accumulation of malic acid and citric acid.The accumulation of total organic acids was regulated by multiple enzymes.The difference in malic acid accumulation is mainly caused by the coordination change of PEPC,NAD-MDH and NADP-ME activities,while the difference in the accumulation of citric acid is mainly affected by the change of CS activity.