Abstract: Browning takes place generally in tissue culture of Juglans mandshurica Maxim. and influences the growth and proliferation of cultures. We established the regeneration system for axillary bud of J.mandshurica Maxim. and studied the factors influencing the browning of cultures by changing culture environment and adding anti-browning agents into the culture medium. The inducing rate of 1-2 year axillary bud as explant was 75.8%, significantly higher than those of 10 and 30 year axillary buds. Browning rate was 56.7%, which was significantly lower than the others. DKW+BA 2.0 mg·L^-1+IBA 0.1 mg·L^-1 culture medium reduced browning and promoted plant growth, and the browning rate was lowered by about 10%. Na₂S₂O₃ and AC effectively alleviated the browning, while the alleviated effect of PVP and VC on browning was not significant. Fiveday dark treatment after inoculation delayed browning time, and the browning rate reduced by about 10%. Adding 6 g·L^-1 agar in culture medium resulted in browning rate of 56.7%. After subculture on DKW+BA 2.0 mg·L^-1+IBA 0.01 mg·L^-1 culture medium, the proliferation coefficient of seedlings was 14.4, and the seedling height was 2.33 cm. There was no significant difference between subculture cycles of 21 and 28 days, and a subculture cycle of 21-28 days was suitable for proliferation culture.

Key words: Juglans mandshurica Maxim., tissue culture, browning, regeneration system