以美味猕猴桃品种‘秦美’果实为材料,研究了其生长发育过程中与AsA代谢循环系统相关的物质抗坏血酸(AsA)、谷胱甘肽(GSH)、草酸(OA)、酒石酸(TA)和过氧化氢(H2O2)的含量及相关酶活性的变化及其相互关系。结果表明:在果实生长发育过程中,花后AsA含量明显增加,花后30d达到最高后开始下降,花后75d后基本保持不变。就整个果实中总的AsA积累量而言,花后开始显著增加,到45d达到最大值后至成熟基本保持不变。这表明猕猴桃果实的AsA积累主要发生在幼果期。GSH随着果实发育在花后120d前其含量及积累量均有增加,但积累也主要发生在幼果期。OA含量的变化与H2O2含量和抗坏血酸过氧化物酶(APX)活性相似,均在花后开始显著下降,到花后30d后变化不大;而TA含量的变化趋势与AsA一致。抗坏血酸氧化酶(AO)、单脱氢抗坏血酸还原酶(MDHAR)和脱氢抗坏血酸还原酶(DHAR)的活性变化基本一致,均在花后开始显著升高,60d达到最大后迅速下降,在90d后至成熟基本保持不变。
In present study, the components including the contents of ascorbic acid (AsA) , glutathione (GSH), oxalic acid (OA), tartaric acid (TA) and hydrogen peroxide (H2O2) and some enzymes activities related with AsA metabolism, were investigated during the growth and development of kiwifruit (Actinidia deliciosa ' Qinmei' ). The results showed that AsA content per gram of fresh fruit increased significantly and reached the maximum at the 30th day after anthesis (DAA), then decreased and maintained essentially constant after the 75th DAA. The ascorbic acid content per fruit increased significantly and reached the maximum at the 45th DAA, and then maintained essentially no change to ripe period. It shows that the AsA is mainly accumulated during the fruit cell division stage. Glutathione was accumulated continuously before the 120th DAA, and the accumulation speed was the fastest in young fruit period. As possible products of AsA degradation, OA showed a similar changes with H2O2 content and ascorbate peroxidase (APX) activity during kiwifruit development, which was decreased fast in the fruit early fast development period before the 30th DAA and was no clear change to maturation, but changes of TA content were similar pattern with AsA content. The activity of ascorbate oxygenase (OA) which can led to oxidation of AsA is similar with activities of monode- hydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) used to recycling oxized ascorbate to AsA during the development, which showed a clear increase before the 60th DAA. then decreased fast and maintained a low level during the fruit maturation period.