Abstract: Seed of Podophyllum hexandrum Royle has the physiological characteristics of long dormancy and low germination in natural conditions. In order to investigate the characteristic of dormancy and find the mechanism of dormancy and the optimal method for breaking the dormancy of P.hexandrum seed, some methods such as isolated embryo cultures, biological identification, soaking seed in GA₃, interaction GA₃ and cold stratification were utilized. The results showed that seed coat and endosperm restriction, physiological after-ripping were principal reasons which caused dormancy. Soaking the seed in 400 mg·L^-1 GA₃ solution for 24 h or in GA₃ solution following cold stratification could break the dormancy. The optimal method was soaking the seed in 500 mg·L^-1 GA₃ solution for 36 h following with cold stratification for 90 d, after this treatment, the germination percentage and power reached 81.11% and 50.00% respectively.

Key words: Podophyllum hexandrum Royle, seed, dormancy, GA₃, cold stratification