冷藏期间苹果果实能量和NADP-苹果酸酶及基因表达的变化

Change of energy level and gene expression of NADP-dependent malic enzyme in apple fruit during refrigerated storage

为研究冷藏期间苹果果实能量水平和NADP-苹果酸酶(NADP-ME)及基因表达的变化情况,本研究以‘长富2’苹果果实为实验材料,定期测定果实硬度、可溶性固形物等品质指标和能量相关物质三磷酸腺苷(ATP)、二磷酸腺苷(ADP)、磷酸腺苷(AMP)含量和能荷变化及NADP-ME、琥珀酸脱氢酶(SDH)活性。结果显示,冷藏期间,‘长富2’果实ATP含量贮藏前60 d下降,而后恢复到贮藏初期水平,ADP和AMP贮藏前60 d稍有降低后,随时间延长显著增加;NADP-ME和琥珀酸脱氢酶(SDH)活性均随贮藏时间延长逐渐降低;辅酶Ⅱ(NADP+)和还原型辅酶Ⅱ(NADPH)含量在贮藏前120 d先增加后下降,与能荷变化相似;Mdcy ME1-Mdcy ME3基因表达虽在时间上有一定差异,但表现出相似的先增加后下降的趋势。冷藏期间苹果果实能量水平和利用效率发生了改变,且能量水平与NADP-ME活性及其基因表达在统计学上存在相关性。

In order to investigate the change of energy level and gene expression of NADP-dependent malic enzyme during storage, ‘ Changfu 2＇ apple fruits were taken as experimental material. Fruit firmness, total soluble solid （ TSS）, the activity of NADP-dependent malic enzyme（NADP-ME） and SDH, contents of ATP, ADP, AMP and energy charge were determined during storage.The results showed that the ATP content in apple fruit during storage period declined for the first 60 days thereafter recovering to storage beginning level ,while the ADP and AMP content in fruit declined slightly for the first 60 days thereafter increased significantly. Both activities of NADP-ME and SDH declined gradually during whole storage period.The content of NADP ＋ and NADPH in apple fruit performed similar trend with the energy charge that all increased obviously for the first 120 days then declined in the last 60 days.Although there was some difference on the time course, the gene expression of MdeyME1-MdcyME3 performed similar trend that they all increased daring the early storage and then declined.These results demonstrated the energy levels and efficiency in apple fruits changed during storage and energy level has relevance with the activities and gene expression of NADP-ME.