为了探讨白菜种子萌发热抑制的机制,以新收获的白菜种子为材料,研究了种子萌发对不同温度的响应,后熟、冷层积和植物激素处理对种子萌发的作用,以及种子萌发和不同处理与细胞壁降解酶之间的关系。结果表明,当萌发温度≥20℃时,种子的萌发率显著降低,热抑制的种子不表现次生休眠。后熟、层积和GA3处理能有效地降低种子萌发的热抑制;相反,ABA处理则增强种子萌发的热抑制。种子萌发过程中内切–β–甘露聚糖酶、β–甘露糖苷酶和α–半乳糖苷酶的活性增加。与新收获的种子相比,后熟、层积和GA3处理增加上述3种酶的活性;ABA处理增加内切–β–甘露聚糖酶的活性,但不影响β–甘露糖苷酶和α–半乳糖苷酶的活性。在不同温度下吸胀48 h的种子的内切–β–甘露聚糖酶和α–半乳糖苷酶的活性变化与随后种子的萌发没有直接关系。说明新收获的白菜种子具有明显的萌发热抑制,这种特性能被后熟、层积和GA3处理以增强细胞壁降解酶活性的方式有效地解除。 In order to explore the mechanism of heat inhibition of seed germination in cabbage, the newly harvested cabbage seeds were used to study the effects of seed germination on the response to different temperatures, the effect of post-ripening, cold stratification and phytohormone treatment on seed germination, and seed germination and seed germination Dealing with cell wall degrading enzymes. The results showed that when the germination temperature was ≥20 ℃, the germination rate of the seeds was significantly reduced, while the seeds of the heat-suppressed seeds did not show secondary dormancy. After ripening, stratification and GA3 treatment can effectively reduce the thermal inhibition of seed germination; on the contrary, ABA treatment enhances the thermal inhibition of seed germination. The activity of endo-β-mannanase, β-mannosidase and α-galactosidase increased during seed germination. Compared with freshly harvested seeds, ripening, stratification and GA3 treatment increased the activities of the above three enzymes. ABA treatment increased the activity of endo-β-mannanase but did not affect the activities of β-mannosidase and α- Galactosidase activity. The changes of the endo-β-mannanase and α-galactosidase activity of seeds which had been swollen for 48 h at different temperatures were not directly related to the germination of the seeds. The results showed that the newly harvested Chinese cabbage seeds had obvious inhibition of germination heat, which could be effectively eliminated by the methods of ripening, stratification and GA3 treatment to enhance the activity of cell wall degrading enzymes.