School of Food Science and Engineering, Hainan University, Haikou, 570228, China.
School of Food Science and Engineering, Hainan University, Haikou, 570228, China; Key Laboratory of Food Nutrition and Functional Food of Hainan Province, Haikou, 570228, China.
Plant Physiol Biochem. 2024 Dec;217:109219. doi: 10.1016/j.plaphy.2024.109219. Epub 2024 Oct 19.
Papaya (Carica papaya L.) is highly susceptible to chilling injury (CI), which primarily causes surface pitting, black scald, susceptibility to fungal infection, and the breakdown of tissue. It developed rapidly at 6 °C but was significantly suppressed at 1 °C, which indicated that the papaya tissue was more solid at a lower temperature. This rare phenomenon is considered to be abnormal CI behavior. The maintenance of fruit tissue integrity during abnormal CI behavior may be related to modifications of the cell wall pectin. The modifications of cell wall pectin were studied during storage at 1 and 6 °C. Storage at 1 °C alleviated the progression of CI and inhibited the degradation of pectin components and cell wall structure of papaya fruit. The increase in water-soluble pectin and the solubilization of cyclohexanediamine tetraacetic acid- (CDTA-) and sodium carbonate (NaCO)-soluble pectin was limited at 1 °C. Storage at this temperature limited the detachment of linear backbone chains and minimized the degradation of branching and reticular structure in the pectin molecules. Storage at this temperature also delayed the decrease in the size of pectin backbone and helped to prevent the loss of neutral sugars from the pectin side chains. Thus, alleviation of the degradation of cell wall pectin contributes to the structural integrity of the cell wall and thus helps the maintenance of the tissue integrity of papaya at 1 °C.
番木瓜（Carica papaya L.）极易受到冷害（CI）的影响，主要表现为表面麻点、黑疤、易受真菌感染和组织崩溃。在 6°C 时，番木瓜的冷害发展迅速，但在 1°C 时明显受到抑制，这表明番木瓜组织在较低温度下更为坚实。这种罕见的现象被认为是异常冷害行为。在异常冷害行为期间，保持果实组织完整性可能与细胞壁果胶的修饰有关。研究了在 1 和 6°C 下贮藏时细胞壁果胶的修饰。在 1°C 下贮藏可缓解冷害的发展，并抑制果胶成分和番木瓜果实细胞壁结构的降解。在 1°C 下，水溶性果胶增加，环己二胺四乙酸（CDTA）和碳酸钠（NaCO）可溶性果胶的溶解受到限制。在这种温度下贮藏限制了线性主链的分离，并最大限度地减少了果胶分子中支链和网状结构的降解。这种贮藏温度还延迟了果胶主链大小的降低，并有助于防止果胶侧链中性糖的损失。因此，减轻细胞壁果胶的降解有助于细胞壁的结构完整性，从而有助于在 1°C 下保持番木瓜组织的完整性。
