Abstract: ： A multi-factor experimental design was used to explore the effects of different environmental conditions such as light, temperature, moisture, salt, plant hormones and heat shock on the germination characteristics of American mint （Monarda didyma） seeds. The results showed that light and gibberellin can significantly promote the germination of American mint seeds, which can shorten the germination time of seeds and increase the germination rate of seeds. Seeds treated with 200 mg/L gibberellin had the highest germination rate of 87.78%. Heat shock treatment shortened the germination time of American mint seeds, and the highest germination rate was at 28 ℃ for 24 h. The best temperature for seed germination is 23~25 ℃, 25 ℃ is conducive to seedling growth. The seed germination rate, germination index and vitality index decreased significantly with the increase of water stress and salt stress. When the concentration of polyethylene glycol （PEG） is 0.15 g/mL, the germination rate is significantly lower than that of the control, and the seeds cannot germinate at 0.20 g/mL. The germination rate of NaCl concentration of 50 mmol/L was significantly lower than that of the control, and the seeds could not germinate at 400 mmol/L.

Key words: environmental factor, gibberellin, 6-BA, heat-shock, Monarda didyma