Abstract
While bulblets of Lilium japonicum Thunb. were being multiplied by tissue culture, the number of leaves emerging from the bulblets gradually decreased as the culture period was prolonged; finally, bulblets developed no leaves. Dormant bulblets which had been cultured in vitro for more than 15 months were exposed to 2°C or treated with BA or GA3.
1. Bulblets incubated at 2°C to break dormancy and subsequently cultured at 20°C developed scale leaves and enlarged. Thus, dormancy prevents leaf emergence and reduces the rate of bulblet enlargement.
2. Bulblets cultured on medium with 2 mg•liter-1 BA or 9.5 or 30 mg•liter-1 GA3 formed leaves. However, leaf emergence was suppressed when the bulblets were transferred to medium with low concentrations of NAA (0.01 mg•liter-1) and BA (0.001 mg•liter-1), indicating that BA and GA3 stimulate leaf emergence directly and do not break dormancy.
