IN VITRO FLOWERING AND FRUITING IN CULTURE OF DENDROBIUM OFFICINATE KIMURA ET MIGO. (ORCHIDACEAE)

Abstract

Dendrobium officinate Kimura et Migo. is a rare and endangered perennial orchid, which is valued for its attractive flowers and medicinal uses. Its three-to-five-year breeding cycle makes propagation difficult, so we investigated In vitro production of flowers and seeds for this species. Calluses were induced from shoot-tip explants of D. officinate on Murashige & Skoog (MS) medium with 0.2 mg L-1 benzyladenine (BA) and 0.05 mg L-1 α-naphthalene acetic acid (NAA). Multiple shoots were regenerated after protocorm-like bodies (PLBs) were transferred onto the same basal medium with 1.0 mg L-1 NAA. The plantlets, 2-4 cm in height, maintained In vitro were induced to flower, and the highest rates of inflorescence (83.2%) and normal flowers (73.6%) were produced on the MS medium with 15% (v/v) coconut water and 0.1 mg L-1 thidiazuron (TDZ) within 9 weeks. Histological analysis showed the origin of the floral primordial and normal morphologies of the pollen and female organs. The normal flowers were artificially pollinated and capsules developed. Viable seeds were produced and most of them germinated on the MS medium. This reproduction system could be used to study the molecular basis of flowering or to improve plant breeding programs.