In vitro development of adventitious shoots in Euonymus alatus (Celastraceae)

Abstract

Mature embryos of Euonymus alatus (Thunb.) Sieb. were excised aseptically from seeds before or after cold treatment and germinated in light on half-strength Murashige and Skoog (MS) medium with 2% sucrose, 0.7% agar, naphthalene acetic acid (NAA) at 0.01 mg l −1 and benzylaminopurine (BAP) at 0.1–0.5 mg l −1. Hypocotyls of these seedlings were cut into 1–2-mm segments and induced to form adventitious shoots on the same medium. Large numbers of shoots, most bearing several pairs of leaf primordia, were produced per isolated hypocotyl segment. These shoots could be further multiplied by axillary bud release on medium containing 0–0.1 mg l −1 NAA and 0.0–0.3 mg l −1 BAP. Adventitious shoot formation began with profuse callus formation, originating in the epidermis of the hypocotyl. Vascular strands differentiated from callus parenchyma were observed extending into surface protuberances and, in older cultures, into adventitious shoot buds. Rooting was induced in vitro by culturing shoots on medium containing 0.4% agar and 3 mg l −1 indolebutyric acid (IBA). Rooted shoots were successfully transferred to vermiculite, hardened off and had the appearance of normal field-grown plants, including the characteristic winged periderm of this species.