Protocorm Regeneration, Multiple Shoot Induction and ex vitro Establishment of Cymbidium devonianum Paxt.

摘要

Cymbidium devonianum Paxt., an epiphytic orchid of considerable ornamental and horticultural importance is an extremely rare and threatened orchid of Northeast India. An efficient method of propagation has been developed via protocorm regeneration from seeds. Seeds obtained from capsules of C, devonianum collected 9 months after artificial pollination developed into protocorms on basal media viz., Murashige and Skoog (MS), Gamborg et al. (B_5) and Mitra et al. Protocorm formation varied in differentmedia. Maximum number (92.8%) of protocorms was observed in B_5 medium. The development of protocorm was also faster (48.0 days) in the same medium. However, in MS medium further development of protocorms into seedlings was faster. Seedlings obtained from protocorms showed optimal fresh weight (0.33 g) and shoot number (5.1 plantler~(-1)) in MS + 1.0 mg L~(-1) of N~6-benzylaminopurine (BAP) + 1.0 mg L~(-1) indole-3-acetic acid (IAA); shoot length (2.9 cm plantler~(-1)) and root number (3.9 plantler~(-1)) in MS + 1.0 mg L~(-1) BAP + 0.5 mg L~(-1) IAA and root length (3.6 cm plantler~(-1)) in MS + 1.0 mg L~(-1) of IAA. Ninety percent of hardened C. devonianum plantlets survived on substratum containing brick, charcoal, decay ing litter (1:1:1) with a layer of moss on top. The given protocol of successful protocorm regeneration should permit rapid propagation and conservation of this rare and threatened Cymbidium species.