This work aimed to study the causes of seed dormancy of Phoebe sheareri, determine the dormancy type, find out the ways to break seed dormancy and explore the best temperature condition for its germination, so as to provide theoretical and technical support for the cultivation of Phoebe sheareri seedlings.

The water permeability and air permeability of the seed coat of Phoebe sheareri and the endogenous inhibitors in seeds were measured to investigate the causes of seed dormancy. The low-temperature stratification treatment was applied to study the method to break the seed dormancy of Phoebe sheareri, and seven temperature treatments including 15 ℃, 20 ℃, 25 ℃, 30 ℃ and 35 ℃ (day and night), 30 ℃ (day) /20 ℃ (night) and 25 ℃ (day) /15 ℃ (night) were set to determine the appropriate temperature for seed germination.

1) Fresh seed coat impeded water absorption and respiration of seeds, the water absorption rate of peeled seeds was 2.24 times that of intact seeds, and the respiration rate of peeled seeds was 1.92 times that of intact seeds, thus fresh seed coat has an inhibitory effect on seed germination; 2) The water and methanol extracts from Phoebe sheareri seeds significantly inhibited the seed germination and seedling growth of cabbage, suggesting that Phoebe sheareri seeds have water-soluble and methanol-soluble endogenous inhibitors; 3) low-temperature stratification can break the dormancy of Phoebe sheareri seeds. With the extension of treatment time, the germination of seeds was advanced, and the germination rate was accelerated and improved. The germination rate of seeds after 100 days of low-temperature stratification was significantly higher than other treatments, up to 98.89%. The effect of GA₃ soaking on seed dormancy release was not ideal; 4) Temperature had a great influence on the germination rate of Phoebe sheareri seeds. The germination ability of seeds under the constant temperature condition of 25 ℃ was higher than that under other temperature treatments.

The poor water permeability and air permeability caused by the seed coat of Phoebe sheareri and the endogenous inhibitors in seeds are the main factors causing seed dormancy. The dormancy of Phoebe sheareri seeds belongs to combined dormancy. Low-temperature stratification is an effective way to break seed dormancy and increase seed germination rate. The optimal temperature for Phoebe sheareri seed germination is 25 ℃.