High frequency of plant production via somatic embryogenesis from callus or cell suspension cultures in Eleutherococcus senticosus

Hypocotyl segments of Eleutherococcus senticosus cultured on Murashige and Skoog's (MS) medium with 4.5 mu M 2,4-D produced somatic embryos directly from the surface of explants without intervening callus formation. When these somatic embryos were subcultured to the same MS medium with 4.5 mu M 2,4-D, friable embryogenic calli were formed mainly from radicle tips of somatic embryos, but at a low frequency (5 %). Selected embryogenic calli were maintained on MS agar or liquid medium with 4.5 mu M 2,4-D. To induce somatic embryo development, embryogenic calli and cell clumps were transferred to MS medium lacking 2,4-D. The frequency of somatic embryo formation differed between culture types with 1570 embryos formed per Petri dish from callus culture and 5514 embryos formed per flask from cell suspension cultures. Somatic embryos formed on agar medium had larger cotyledons than those of embryos formed in liquid medium. GA. treatment was necessary to induce germination from somatic embryos. The rate of plant conversion was 97% in somatic embryos from callus culture and 76% in embryos from liquid culture. Regenerated plantlets were successfully acclimatized in the glasshouse. (C) 1999 Annals of Botany Company.