In vitro conservation and asymbiotic propagation of Coelogyne flaccida (Lindl.): A threatened orchid

Asymbiotic seed germination of Coelogyne flaccida varied with the capsule stage and the culture medium used for germinating seeds. The capsules were harvested at two different stages of development. The seeds were cultured on three asymbiotic orchid seed germination defined and undefined media, i.e. Mitra (M) medium, Murashige and Skoog (MS) medium and potato dextrose agar (PDA) medium. The seeds obtained from undehisced green capsules germinated with a maximum germination percentage (84.50 +/- 0.33%) on M medium followed by MS and PDA medium. The effect of cytokinins, such as 6-benzylaminopurine and furfurylaminopurine and the synthetic auxin alpha-naphthalene acetic acid, on seed germination was also assessed. Simultaneously, in vitro multiplication using protocorms as explants was also studied. The effect of organic growth supplements, such as banana homogenate (BH, 25, 50, 75gl(-1)) and peptone (P, 1.0, 1.5, 2.0gl(-1)), was tested on the de novo formation of protocorm-like bodies (PLBs), development of the maximum number of shoots and early formation of plantlets using the M medium. Among the treatments, the highest regeneration frequency (87.50 +/- 0.20%) and the highest number of PLBs per explant (10.25 +/- 0.50) were obtained in P (1.5gl(-1))-supplemented cultures, and the plantlets were formed within 18weeks of culture. BH favoured the development of healthy plantlets, with a maximum fresh weight of 1.02 +/- 0.04g per plantlet.