A Comparative Study on Postharvest Cold Tolerance in Salicylic Acid-Deficient Mutant (NahG) and Wild-Type Tomato Fruits

In this study, postharvest salicylic acid (SA)-deficient mutant (NahG) and wild-type (WT) tomato fruits were stored at 4 ℃ for up to 28 days. Chilling injury symptoms were observed, and chilling injury index, the activities of phospholipase C (PLC), phospholipase D (PLD), lipoxygenase (LOX), polygalacturonase (PG) and cellulase, and the contents of proline, lignin, cellulose, total phenols and catechinic in the fruits were measured during the storage period. Compared with the WT fruit, chilling injury index and the activities of PLC, PLD, LOX, PG and cellulase in the NahG fruit were lower, whereas the contents of proline, lignin, cellulose, total phenols and catechinic were higher. These results suggest that the degradation of cell membrane and cell wall is alleviated and the contents of cold tolerance-related compounds are increased in the NahG fruit. Therefore, it had stronger cold tolerance than the WT fruit.