Study on Gentiana crassicaulis Duthie ex Burk. crude extracts and method for breaking dormancy

We investigated the dormancy mechanism of Gentiana crassicaulis Duthie ex Burk. seeds, as well as the applicable technology to break the seed dormancy and encourage rapid germination. The water absorption of seeds and activity of crude extracts were determined using dried G. macrophylla seeds, which were dry stored for after-ripening. We conducted the germination experiment by soaking seeds in priming solutions of gibberellic acid (GA₃), potassium permanganate (KMnO₄), polyethylene glycol(PEG6000) or hydrogen peroxide (H₂O₂), and then compared seed germination under the different treatments. Results showed that the G. crassicaulis seed capsules did not impede water absorption to any great extent. At the different concentrations, the crude extract showed inhibitory effects on the germination and growth of Chinese cabbage and wheat, and a certain inhibition effect on the germination of G. crassicaulis, which was the most significant (P < 0.05) when the concentration reached 0.1 g/mL. The KMnO₄ treatment significantly improved the germination rate of G. crassicaulis seeds and was the most significant (P<0.05) at a concentration at 1.5%, whereas treatment with H₂O₂ had a much less significant effect. In addition, soaking with 500 mg/L of GA₃ and priming with 300 mg/L of PEG6000 disturbed the seed dormancy of G. crassicaulis (P < 0.01). Our research showed that the seed endogenous inhibition of G. crassicaulis is one of the factors affecting dormancy, and that the seed mechanical barrier affects seed germination to a certain extent. The G. crassicaulis seeds showed comprehensive dormancy characteristics. Soaking the seeds with KMnO₄ and GA₃ and priming with PEG6000 interrupted seed dormancy, shortened germination time, and promoted germination.