Suitable Conditions for the Induction and Micropropagation of PLBs in Some Monopodial Orchids

Abstract

Liquid media suitable for the induction and micropropagation of protocorm-like bodies (PLBs) in Vandofinetia Nara ‘Yumika Pink’ were developed by modifying MS basal medium. The best medium obtained for PLBs induction was one-fourth strength MS medium containing 30g/l sucrose and for PLBs micropropagation was one-fourth strength MS medium containing 10g/l sucrose in which FeEDTA was replaced by 6.95mg/l FeSO₄7H₂O. Usefulness of the latter medium was confirmed in other monopodial orchids such as Renanetia, Darwinara, Ascocentrum and Ascofinetia. After transfer onto 2g/l Hyponex (N:P:K=10:30:20) medium containing 2g/l proteose peptone and 20g/l sucrose for 2 months, the PLBs (both those regenerating and those not regenerating plantlets) were subcultured into MS medium containing 30g/l sucrose at 2 months intervals for 4 months. More than 10, 000 plantlets ready for transplanting to pots were obtained efficiently from one floral bud within a year for each orchid cultivar. These results suggest that the methodology could be used on a commercial scale for micropropagation of a wide range of monopodial orchids.