Establishment of thin cross section (TCS) culture method for rapid micropropagation of Cymbidium aloifolium (L.) Sw. and Dendrobium nobile Lindl. (Orchidaceae)

An efficient and reproducible procedure is outlined for rapid in vitro multiplication of two commercially important orchids Cymbidium aloifolium (L.) Sw. and Dendrobium nobile Lindl. through high frequency shoot proliferation from thin cross sections (TCSs) of protocorm-like bodies (PLBs). The TCS were cultured on Murashige and Skoog's medium supplemented with any of the three cytokinins such as zeatin riboside (ZR), N-6-benzyladenine (BA) or kinetin (Kn). For induction of PLBs, ZR at 14.0 muM was most effective for C. aloifolium while BA at 11.0 muM was optimum for D. nobile. Average number of PLBs per TCS explant was high in both the cases (28.2 in C. aloifolium, and 34.0 in D. nobile) though inhibitory effect was noticed with cytokinins above the optimal level. PLB development from TCS explants in both the species was enhanced by the use of suspension culture. High frequency of shoots (85% in C. aloifolium and 80% in D. nobile) regenerated of PLBs were rooted on MS medium containing 9.8 muM indole-3-butyric acid (IBA). Regenerated plants were successfully acclimatized and eventually transferred to the field. (C) 2002 Elsevier Science B.V. All rights reserved.