Asymbiotic seed germination and in vitro seedling development of Epidendrum ibaguense Kunth. (Orchidaceae)

Abstract

Effects of four asymbiotic media; Murashige and Skoog (MS), Phytamax (Sigma, USA; PM), Mitra et al. (M) and Knudson ‘C’ (KC) were evaluated for seed germination and early protocorm development in Epidendrum ibaguense Kunth. Besides, effects of peptone, activated charcoal and plant growth regulators (6-benzylaminopurine (BAP) and 2,4-dichlorophenoxyacetic acid (2,4-D)) were also studied. Maximum seed germination was achieved on M and PM (~90%) fortified with 2 gl-1 peptone. Medium supplemented with 1.0 mgl-1 BAP improved seed germination in contrast to basal media whereas 2,4-D either singly or in combination with BAP remarkably reduced the germination rate. Activated charcoal in the medium enhanced germination of seed, induced significantly large size protocorms (1.63±18) and
early rooting in protocorms. Within two weeks of culture, spherules emerged out due to cracking of the seed coat. The spherules developed into protocorms with a leaf primordium at apical portion after 3 to 4
weeks and gradually produced complete seedlings. Strong and stout root system was induced in in vitro seedlings on transferring in half strength PM and M media fortified with 0.5-1.0 mgl-1 indole acetic
acid (IAA). Well-rooted seedlings were transferred to green house with 90% survival.