Plant regeneration through somatic embryogenesis of a medicinal plant, Phellodendron amurense Rupr.

Somatic embryogenesis and subsequent plant regeneration were established from hypocotyl and internode explants collected from in vitro-grown seedlings and in vitro-proliferated shoots, respectively. Somatic embryogenesis was significantly influenced by the types of auxin and cytokinin. Friable calluses with somatic embryos developed well in Murashige and Skoog basal (MS) medium supplemented with 0.8-8.8 mu M 6-benzylaminopurine (BA) and 2.0-8.0 mu M 2,4-dichlorophexoxyacetic acid (2,4-D) or alpha-naphthaleneacetic acid (NAA). The maximal frequency of embryogenic callus and somatic embryo formation were obtained when the MS medium was amended with 8.8 mu M BA and 4.0 mu M 2,4-D. The best embryo germination occurred in a hormone-free 1/2-MS medium. The highest percentage of shoot proliferation was observed in embryogenic calluses in MS medium containing 2.0 mu M BA and 1.0 mu M NAA. In vitro-grown shoots were rooted in MS medium with 0.5-2.0 mu M indole-3-butyric acid. Regenerants were transferred to vermiculite and successfully established under an ex vitro environment in garden soil.