Abstract The mechanism by which modified-atmosphere packaging (MAP) protects the quality of whole lettuce (Lactuca sativa L. Grand Rapid) was investigated in this study. MAP-treated lettuce exhibited a low respiration rate, weight loss, chlorophyll loss, and relative conductivity, together with improved overall quality. Transmission electronic microscopy (TEM) was used to reveal the integrated mitochondrial morphology in MAP-treated lettuce, and a further analysis found that MAP treatment could increase the calcium (Ca2+) content and Ca2+pump activity. MAP-treated lettuce also displayed low levels of the superoxide anion and hydroxyl radical, which was explained by a stable electron transport chain (ETC), as evidenced by high succinate dehydrogenase and cytochrome c oxidase activity. It was further found that MAP could increase superoxide dismutase and ascorbate peroxidase activity, as well as the ascorbic acid and glutathione content. These findings suggest that MAP maintains the quality of postharvest whole lettuce by protecting the mitochondrial structure and maintaining the ETC balance.

中文翻译：

---

气调包装通过调节电子传递链的动态平衡和保护线粒体结构和功能来保持采后整株生菜 (Lactuca sativa L. Grand Rapid) 的质量

摘要 本研究探讨了气调包装(MAP) 保护全生菜(Lactuca sativa L. Grand Rapid) 品质的机制。MAP 处理的生菜表现出较低的呼吸速率、重量减轻、叶绿素损失和相对电导率，同时提高了整体质量。透射电子显微镜 (TEM) 用于揭示 MAP 处理的生菜中整合的线粒体形态，进一步分析发现 MAP 处理可以增加钙 (Ca2+) 含量和 Ca2+ 泵活性。MAP 处理的生菜还显示出低水平的超氧阴离子和羟基自由基，这可以通过稳定的电子传递链 (ETC) 来解释，高琥珀酸脱氢酶和细胞色素 c 氧化酶活性证明了这一点。进一步发现MAP可以增加超氧化物歧化酶和抗坏血酸过氧化物酶的活性，以及​​抗坏血酸和谷胱甘肽的含量。这些发现表明 MAP 通过保护线粒体结构和维持 ETC 平衡来保持采后整株生菜的质量。