Study on the Method of Breaking Seed Dormancy of Platycodon by Exogenous Hormone

[Objective] The study was to provide the method to break seed dormancy of Platycodon.[Method] With seeds of Platycodon as tested material,each 6 concn treatments were set up for GA3,NAA and 6-BA with no pretreatment as CK to study the seed germination of different treatments.[Result] Soaking seeds in the solution with 50-250 mg/L GA3 for 24 h could promote the seed germination.Compared to CK,the seed germination rate,vigour and index after soaking in GA3 solution were increased obviously and the treatment of soaking with 250 mg/L GA3 for 24 h had a best effect.Compared with CK,the seed germination rate,vigour and index after soaking in NAA solution with different concn.were increased partly and decreased partly.Compared with the treatment of distilled water,the seed germination rate,vigour and index after soaking in NAA solution were all decreased.Compared with CK,the treatment with low concn.of 6-BA could significantly promote seed germination,but the treatment with high concn.of 6-BA could restrain the seed germination.Compared with the treatment of distilled water,the seed germination rate,vigour and index after soaking with different concn.6-BA solution were all decreased.[Conclusion] Soaking the seeds in solution with 50-250 mg/L GA3 for 24 h had a best effect of breaking seed dormancy of Platycodon.