Ecology, Environment and Conservation Paper

IN VITRO CONVERSION OF ROOT MERISTEM INTO PROTOCORM LIKE BODIES IN RHYNCHOSTYLIS RETUSA-AN ENDANGERED FOX TAIL ORCHID

Vishal Sharma

Abstract

The regenerative potential in the root ex plants of in vivo grown Rhynchostylis retusa plants largely depend on the location of isolated ex plants from the main root and on the level and type of the growth regulators Regeneration in root ex plants (0.5 cm) from in vivo plants shows basipetal gradient regeneration all along the root axis. The distal ones with intact tips showed an extended growth (1.2-1.9 cm) in 8 wk old cultures regardless of the chemical regime, however, the proximal explants responded to the presence of cytokinins (BAP/KN) in Mitra et al., (1976) medium. The effect of cytokinins is accentuated in the additional presence of NAA, BAP (3mg/L) when used with NAA(1mg/L) favoured indirect somatic embryogenesis (callus), however, when KN replaced BAP in the latter medium, the plant regeneration switch to direct somatic embryogenesis mediated regeneration. Maximum number of shoots is obtained with cytokinin to auxin in ratio of 3:1 in BM+BAP+NAA in 31.25±6.25 ex plants forming 28 plant lets in 15 weeks. The pure-line stability of regenerates is confirmed at chromosome level (2n=38). The root regenerated plant lets exhibit more genetic stability and showed better acclimatization frequency with 90% success.