Abstract: Adventitious shoots were successfully regenerated from hypocotyl explants of in vitro culture of Euonymus japonicus 'Cu zhi'. Hypocotyl slices were cultured on Murashine and Skoog (MS) and B5 basal medium supplemented with various plant growth-regulators. Two auxins, ?-naphthaleneacetic acid (NAA) and indole-3-butyric acid (IBA) combined with two cytokinins, 6-benzylaminopurine (6-BA) and kinetin were tried. The study showed that shoot regenerated directly from hypocotyl explants without the intervening callus phased. MS medium was more suitable for adventitious shoots regeneration. The ability of hypocotyl segments to produce shoots varied depending upon their positions on seedlings. The highest regeneration rate was obtained with hypocotyl segments near the cotyledon cultured on MS basal medium supplemented with 1.5 mg·L-1 BA and 0.05 mg·L-1 NAA (63.64%). The regenerated shoots were readily elongated on the same medium as used for multiplication and rooted on half-strength MS basal medium supplemented with 1.0 mg·L-1 IBA and 100 mg·L-1 activated carbon. The plantlets were subsequently transferred to greenhouse conditions, and 96% of them were successfully acclimatized.

Key words: Euonymus japonicus 'Cu zhi', in vitro culture, Hypocotyl explants, Adventitious shoots, Plant regeneration