Effect of plant growth regulators,temperature and sucrose on shoot proliferation from the stem disc of Chinese jiaotou (<Emphasis Type="Italic">Allium chinense</Emphasis>) and in vitro bulblet formation

In vitro shoot proliferation from stem disc of Allium chinense, a vegetatively propagated plant, was investigated in this experiment. In the present study, shoots were formed directly on stem discs on a medium containing 1 mg/l N⁶-benzyladenine (BA) and 0.5 mg/lα-naphthaleneacetic acid (NAA). These shoots were further cultured on MS media supplemented with various levels of BA in combination with NAA, and new shoot clusters developed easily from the explants cultured despite considerable differences in the induction of shoot clusters with different levels of BA and NAA. The most productive combination of growth regulators proved to be 1.0 mg/l BA and 1.0 mg/l NAA, in which about 17 shoots were produced per cluster in 8 weeks culture. Most of the formed shoots were rooted 15 days after being cultured on MS media supplemented with 0.1–1.0 mg/l NAA. The survival rate of the plantlets under ex vitro conditions was 95% in pots filled with a peat: sand (2:1 v/v) mixture after two weeks. In vitro bulblet formation were strongly promoted by the high temperature of 30°C compared to that at 25, 20 and 15°C, and 12% (w/v) sucrose appeared to be optimal for bulblet development. Results from this study demonstrated that A. chinense could be in vitro propagated by using stem discs and in vitro bulblet formation could be achieved.