2022, Vol. 10, Issue 2, Part C

author(s)
Kuntala N Barua, Bebija L Singha, Satyam Bordoloi and Bonanya Bora

abstract
Eastern Himalaya owing to its specific gradient and varied climatic conditions has cradled the wonderful natural heritage of temperate and sub-tropical orchids. Large scale forest conversion and over exploitation has brought the orchid diversity to the brink of extinction. Increasing vulnerability of these species it is an urgent need for conservation. In vitro seed propagation is the popular multiplication technique and indispensable components for conservation and restoration of rare and endangered orchids. Study highlighted In vitro seed propagation of ten magnificent orchid species of Northeast India viz. Aerides multiflora, Cleisocentron pallens, Cymbidium aloifolium, Dendrobium aduncum, Dendrobium fimbriatum, Dendrobium lituiflorum, Dendrobium moschatum, Phalaenopsis mannii, Phaius tankerville and Rhynchostylis retusa. MS medium exihibited better proliferation of seeds followed by Mitra et al medium. Lower amount of BAP was most effective for transforming the spherules into fully developed protocorm like bodies. Study revealed that, culture media supplemented with 1.5, mgL^-1 BAP recorded maximum number of shoot (3.9±0.88) with length of 5.56±0.58 cm. for A. multiflora. Highest number (11.2±1.75, 4.1±0.74) and elongation of shoot (4.75±0.58 cm, 5.13±0.85 cm) were recorded in 1.5 mgL^-1 BAP and 0.5 mgL^-1 IBA after 8 week of the culture for C. pallens and R. retusa respectively. However, media supplemented with 0.2% activated charcoal Powder, 0.2% potato extract, 0.2% yeast extract and 0.2% banana extract as natural additives showed excellent performance. MS medium supplemented with TDZ (1.5 mgL^-1) was best phytohormons for shoot elongation of D. moschatum. Root establishment of majority of species found high when medium supplemented by IBA (1.5 mgL^-1). Highest survivality of seedlings established in potting medium containing Brick chips: Charcoal: Sphagnum moss (1:1:2).