This study aims to investigate the effects of cold and salicylic acid (SA) priming on osmolytes accumulation in wheat leaves under freezing stress and its underlying physiological mechanism. The results showed that cold and SA priming treatment significantly enhanced sucrose and free proline contents as compared with non-priming treatment under freezing, resulting in increased leaf water potential, reduced cell death and boosted freezing tolerance. Cold and SA priming-induced free proline accumulation under freezing not only depended on promoting its synthesis, but also on inhibiting its degradation. Interestingly, the synthesis and hydrolysis of sucrose were both increased by cold and SA priming treatment under freezing. Besides, cold and SA priming up-regulated the catabolism of glucose and the assimilation of ammonia as compared with non-priming treatment under freezing stress. Findings of the present study suggested that cold and SA priming could simultaneously promote-free proline and sucrose accumulation in wheat leaves by coordinating carbon and nitrogen metabolism under freezing conditions, and then conferring tolerance to freezing stress. These findings could provide a new insight into the mechanisms by which cold and SA priming enhanced freezing tolerance in wheat.

本研究旨在研究冷和水杨酸（SA）引发对冷冻胁迫下小麦叶片渗透质积累的影响及其潜在的生理机制。结果表明，与冷冻条件下未引发处理相比，冷处理和SA引发处理显着提高了蔗糖和游离脯氨酸含量，导致叶水势增加，细胞死亡减少，抗冻性增强。冷冻和SA引发诱导的游离脯氨酸积累不仅依赖于促进其合成，还依赖于抑制其降解。有趣的是，蔗糖的合成和水解都通过冷冻和 SA 引发处理而增加。除了，与冷冻胁迫下的非启动处理相比，冷启动和 SA 启动上调了葡萄糖的分解代谢和氨的同化。本研究结果表明，冷启动和 SA 启动可以通过协调冷冻条件下的碳和氮代谢，同时促进小麦叶片中游离脯氨酸和蔗糖的积累，然后赋予对冷冻胁迫的耐受性。这些发现可以为冷启动和 SA 启动增强小麦抗冻性的机制提供新的见解。