以软溶质型桃‘雨花三号’（Prumus persica (L.) Batsch, cv. Yuhua3）和硬溶质型桃‘加纳岩’（Prumus persica (L.) Batsch, cv. Jianayan）果实为试材，研究不同溶质型桃果实采后贮藏过程中呼吸速率、乙烯释放量、细胞色素氧化酶（cytochrome c oxidase，COX）活性以及线粒体编码的COX 3 种亚基（COXⅠ、COXⅡ、COXⅢ）基因表达量的变化。结果表明：‘雨花三号’桃果实贮藏过程中，硬度不断下降，且在贮藏后期伴随着呼吸高峰和乙烯释放高峰的出现；而‘加纳岩’在贮藏过程中，硬度下降较缓慢，乙烯释放量较少，呼吸速率较平稳。两种溶质型桃果实在贮藏前期，COX活性不断增加，但到贮藏后期，COX活性下降。‘雨花三号’桃果实中COX活性三种亚基基因的表达量显著低于‘加纳岩’。COX主要作用于桃果实贮藏前期，为果实后熟提供足够能量，贮藏后期表达量降低，活性受影响，机体代谢失衡，线粒体编码的COX与桃果实采后衰老之间存在一定的内在联系。

Soft flesh peach ‘Yuhuasanhao’ (Prumus persica) and stony hard peach ‘Jianayan’ (Prumus persica) were used as test materials, and the changes in the ethylene production, respiration rate, activity of cytochrome c oxidase (COX), and the gene expression of three mitochondrial DNA encoded subunits of COX (COX I, COX II, and COX III) in peach fruit with different flesh types during postharvest storage were studied. The results showed that during postharvest storage, the firmness of 'Yuhuasanhao' peach fruit decreased continuously, and the ethylene production and respiration rate peaked during the late storage period. The firmness of 'Jianayan' peach fruit decreased slowly, with low ethylene production and a stable respiration rate. For both the peach cultivars with different flesh types, the activities of COX increased continuously at the early stage and decreased at the later stage of storage. The activity of COX and the relative expressions of the three mitochondrial DNA encoded subunits of COX were lower in 'Yuhuasanhao' than those in 'Jianayan'. COX played an important role in the early storage period, providing enough energy for postharvest ripening of the peach fruits. At the later stage of the storage period, the expression of the COX genes declined, COX activity was decreased, and there was an imbalance in cellular metabolism. These results suggest the existence of certain intrinsic relationships between COX and peach fruit softening and senescence during the postharvest period.

国家自然科学基金项目(31101586)；江苏省科技计划项目资助（BC2013401）；江苏省自然科学基金项目(BK2010310)