Effects of naphthaleneacetic acid and benzyladenine on the growth of white callus and formation of bulblet from callus induced from mother-scale of Lilium japonicum Thunb

To propagate efficiently bulblets of Lilium japonicwn Thunb., two experiments were conducted : Experiment 1. White calli, induced from scales of a mother bulb were cultured on MS-media containing various concentrations of NAA (0, 0.01 and 0.1 ppm) and BA (0, 0.25, 1.0 and 2.5 ppm) at 25 °C under 300 lx of continuous light for 8 weeks. The optimum concentration for the growth of white callus was the combination of 0.01 ppm NAA and 1.0 ppm BA. The significant differences occurred between treatments. Experiment 2. The effects of NAA and BA on regeneration of bulblets from the white callus were examined. The white callus (about 64 mm3) was cultured in MS-media containing various concentrations of NAA (0, 0.01 0.1 and 1.0 ppm) and BA (0, 0.01 and 0.1 ppm) at 25 °C under 2000 lx of continuous light for 12 weeks. Adventitious globular buds formed on the callus on hormone-free medium after 3 weeks in culture. Bulblets developed from the adventitious buds after 6 weeks. The combination of 1.0 ppm NAA and no BA suppressed bulblet formation but induced only roots from the callus. Conversely, 0.1 ppm NAA and 0.1 ppm BA promoted the growth of the white callus and the formation of abnormal bulblets. Consequently, the media with no or low concentrations of plant growth hormones were optimal for the normal bulblet formation.