Rapid propagation of Eleutherococcus senticosus via direct somatic embryogenesis from explants of seedlings

Explants from three different parts (cotyledon, hypocotyl or root) of one w eek-old seedlings of Eleutherococcus senticosus were cultured on Murashige and Skoog (MS) medium with 1.0 mg l(-1) 2,4-D. Somatic embryos were formed directly from the surfaces of explants. The frequency of direct somatic emb ryo formation was the highest in the hypocotyl segments (75%) as compared t o cotyledon (56%) or root segments (12%). When hypocotyl explants from 3 di fferent stages of seedlings (zero, one or three week-old) were cultured on MS medium with 1.0 mg l(-1) 2,4-D, the frequency of somatic embryo formatio n rapidly declined as the zygotic embryos germinated. However most somatic embryos (93%) from explants of zygotic embryos developed as fused state (mu ltiple embryo), whereas somatic embryos (over 89%) from more developed seed lings developed into single state (single embryo). Single embryos germinate d and regenerated into plantlets with both shoots and roots, while multiple embryos only regenerated into only multiple shoots. Plantlets that regener ated from single embryos of E. senticosus were acclimatized in a greenhouse .