Micropropagation of Echinosophora koreensis Nakai, a Korean Endemic Species in Danger, Using Axillary Buds

To establish in vitro axillary bud culture conditions of Echinosophora koreensis Nakai, one of Korean endemic endangered species famous for beautiful flowers, we tested the influence of plant growth regulators (PGRs) in shooting and rooting stage from in vitro plants. In shoot multiplication, addition of 6-benzylaminopurine (BA) to the media induced 2.5 to 3 shoots per bud during 4 weeks of culture. And media including 0.5 mg L^-1 thidiazuron (TDZ) produced 3 to 4 shoots per bud. However, zeatin and isopentenyl adenine (2-ip) were not successful to increase shoot number, and the combination treatments of BA with other PGRs were also not effective. Shoots were smaller than 2 cm in length, in most of the treatments. In rooting, naphthalene acetic acid (NAA) treatments in the range of 0.5 to 4.0 mg L^-1 appeared to increase rooting rate by 10% to 60% approximately when compared with the control but roots developed with callus clusters. Indole butyric acid (IBA) addition had little effect on rooting (below 10%), while some roots were longer than in NAA treatments and some shoots were longer on high IBA concentrations (4.0 to 8.0 mg L^-1). It is suggested that micropropagation is a highly applicable and promising to multiplication and conservation of rare and endangered endemic species.