Papaya fruits ripen and deteriorate rapidly after harvest. It is well established that the calcium treatment delays fruit ripening. However, the regulation of fruit ripening by calcium treatment in papaya remains unclear. In the present study, we investigate the effect of calcium chloride treatment (2.5% CaCl₂ solution immersion for 15 min), which significantly delayed the ripening of papaya fruit. Fruit yellowing was delayed by 4 days in CaCl₂‐treated fruits compared with control. CaCl₂ treatment significantly delayed loss in fruit firmness and an increase in the total soluble solid content, relative conductivity, and ethylene peak, as well as reduced ethylene production. It inhibited the activity of cell wall degrading enzymes and the expression of cell wall softening‐related genes and ethylene signal pathway‐related genes. These findings indicate that the CaCl₂ treatment delays the ripening and softening of papaya fruits by inhibiting the expression of enzymes and genes related to cell wall degradation and ethylene signal transduction.

中文翻译：

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收获后氯化钙处理延迟木瓜果实的成熟和软化

木瓜果实成熟后收获后会迅速变质。众所周知，钙处理会延迟果实的成熟。然而，通过木瓜中钙处理对果实成熟的调控仍不清楚。在本研究中，我们研究了氯化钙处理（2.5％CaCl ₂溶液浸泡15分钟）的效果，该处理显着延迟了木瓜果实的成熟。与对照相比，CaCl ₂处理的水果的水果变黄延迟了4天。氯化钙₂处理显着延迟了水果硬度的损失，并增加了总可溶性固形物含量，相对电导率和乙烯峰的增加，以及乙烯产量的减少。它抑制细胞壁降解酶的活性以及细胞壁软化相关基因和乙烯信号通路相关基因的表达。这些发现表明，CaCl ₂处理通过抑制与细胞壁降解和乙烯信号转导有关的酶和基因的表达而延迟了木瓜果实的成熟和软化。