Bulblet regeneration in vitro from bulb-scales of Fritillaria thunbergii

Fritillaria thunbergii (Liliaceae), commonly known in Chinese as zhebei, is a perennial plant native to China with important medicinal and ornamental value. Wild populations are at a risk of rapid eradication, and are now very difficult to find. In order to protect wild resources and to set up an efficient system of rapid propagation, sections of bulb-scales from the vegetative period were used to regenerate bulblets in vitro. Surface-disinfected sections were cultured in Murashige and Skoog (MS) medium containing 35 g L^-1 sucrose and supplemented with different types, concentrations and combinations of plant growth regulators [α-naphthaleneacetic acid (NAA), 6-benzyladenine (BA), 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin (KT)]. Bulblets were successfully induced from scale sections after 12 weeks of culture via two pathways. In the first pathway, callus was induced within 5 weeks from scale sections on solid MS medium that was supplemented with 0.5 mg L^-1 BA and 2.0 mg L^-1 NAA. After placing callus at low temperature (4°C) for 3 weeks, bulblets developed on the same medium within 4 weeks (11.3 bulblets explant^-1). In the second (less effective) pathway, bulblets could be induced directly from scale sections on solid MS medium supplemented with 2.0 mg L^-1 BA and 0.5 mg L^-1 NAA, or 1.0 mg L^-1 BA and 0.1 mg L^-1 2,4-D, resulting in 8.2 and 7.8 bulblets explant^-1, respectively. This is a simple but effective protocol for the mass propagation of F. thunbergii.