Abstract:The effects of culture medium composition and culture conditions on pollen germination and pollen tube growth of Chimonanthus praecox (L.) Link.were investigated with liquid culture.The results showed that:(1)PEG 4000 was an essential culture constituent for in vitro culture to C.praecox.The pollen did not germinate in the culture medium without PEG 4000;(2)Low concentration of sucrose in the medium had no effects on pollen germination and pollen tube growth.Whereas,relative high concentration of sucrose significantly inhibited pollen germination and pollen tube growth;(3)0~250 g/L PEG 4000,0~50 mg/L H3BO3,and 0~30 mg/L Ca(NO3)2·4H2O could stimulate pollen germination and pollen tube growth,but higher concentration of these constituents (250 g/L PEG 4000,50 mg/L H3BO3,and 30 mg/L Ca(NO3)2·4H2O) displayed inhibition;(4)Magnesium and potassium had no significant effects on pollen germination and pollen tube growth.In summary,the optimum culture medium composition for liquid culture to C.praecox consist of 250 g/L PEG 4000,50 mg/L H3BO3,and 30 mg/L Ca(NO3)2·4H2O.The optimum culture conditions for pollen germination and pollen tube growth of C.praecox involved pH 5.5,15℃,and 600 lx of illumination.