Seeds of rough gentian (G. scabra), a Chinese herbal medicine, were soaked in 0, 50, 100, 150, 200, 250, 300, 350, and 400 μg/litre of gibberellic acid (GA) for 24 h. After germination, the seedlings were cultured in Germinator at 26°C. Testing for a water-soluble endogenous inhibitory substance showed that the seeds contained an inhibitory substance. The inhibitory substance not only strongly inhibited the growth of young roots and seed germination of Chinese cabbage, but also inhibited its own seed germination. The endogenous inhibitory substance could partly be removed by soaking seed in water at room temperature. Seeds treated with 150 μg GA/litre had the highest percentage germination (79.8%).
