枣发育过程中抗坏血酸合成机制研究

Study on the Synthesis Mechanism of Ascorbic Acid during the Development of Jujube

枣是人类的抗坏血酸(AsA)来源,以富含AsA的沾化冬枣、山东大枣、乐陵金丝小枣果实为实验材料,测定不同发育时期枣果实中AsA的含量与相关酶活性的变化.结果表明,在枣果实发育过程中L-半乳糖1,4-内酯脱氢酶活性(GalLDH)变化和单脱氢抗坏血酸还原酶(MDHAR)活性变化与抗坏血酸含量变化保持高度的一致性,L-半乳糖1,4-内酯脱氢酶和MDHAR很可能是枣果实发育过程中的关键酶.半乳糖脱氧酶(GaLDH)、脱氢抗坏血酸还原酶(DHAR)与抗坏血酸的积累无显著相关性,实验还表明坏血酸氧化酶(AO)在枣果实发育后期可能对枣积累抗坏血酸有一定抑制作用,低活性的AO可以促进抗坏血酸的积累.

Jujube fruits is the source of vitamin C. In this experiment,the content of AsA and the activities of related enzymes in three kinds jujube fruits (Zhanhuadongzao,Shandongdazao,Laolingjinsixiaozao) were determined during fruits development. The results showed that L-galactose 1,4-lactone dehydrogenase (GalLDH) and Monodehydroascorbate reductase (MDHAR) is highly consistent changes in activity and ascorbic acid content,indicating that the GalLDH and MDHAR is likely to be a key enzymeduring jujube fruit development. There were no significant relationship between activities of galactose dehydrogenase (GaLDH),dehydroascorbate reductase (DHAR)and ascorbic acid accumulation. The results also showed that ascorbic acid oxidase (AO) in the late stage of the fruit development of jujube jujube could inhibit the accumulation of ascorbic acid,but also can be said that low activity of AO can promote the accumulation of ascorbic acid.