Abstract: Two-year-old Platycodon grandiflorum(Jacq.)A.DC trees grown in the experiment field of Xiangju Pharmacy Limited Company were used as the materials. The effects of culture medium, sucrose, PEG, pH value, culture time and temperature on the pollen germination and tube growth of P.grandiflorum were investigated using the method of liquid culture. The results showed that: (1)the concentration of 100-150 g·L^-1 PEG could accelerate pollen germination and the growth of pollen tube, the range of 200-250 g·L^-1 PEG could remarkably accelerate pollen germination, however, its function on the growth of pollen tube was not distinct. (2)100 g·L^-1 sucrose was helpful for the pollens to germinate and grow, however, high concentration of sucrose can would strongly inhibit pollen germination and the growth of pollen tubes. (3)the optimum culture medium for pollen germination and growth of Platycodon were ME3+BK+10% sucrose+150 g·L^-1 PEG (pH 5.8). (4)pollen germination was better at 25-40℃, and it was best at 30℃ for 1.5 h.

Key words: Platycodon grandiflorum, pollen, germination In vitro, growth of pollen tubes