Callus-mediated Somatic Embryogenesis and Plant Regeneration in Vanda tricolor Lindl. var. Pallida

Abstract

In this study, a protocol to induce indirect somatic embryogenesis from the basal leaf segments of Vanda tricolor Lindl. var. Pallida has been developed. The experiments consisted of two stages' i.e. induction of SEs from calli and regeneration of plantlet from SEs. Embryogenic calli obtained from previous experiment (0.05 mg L-1 NAA + 0.01 mg L-1 BAP) were used to induce somatic embryos (SEs) on half-strength Murashige and Skoog (MS) medium supplemented with (0.05 mg L-1 to 0.20 mg L-1) 6-benzylaminopurine (BAP) alone or in combination with 0.01 mg L-1 α-naphtalene acetic acid (NAA). Embryogenic calli, those cultured on 0.05 mg L-1 BAP and 0.01 mg L-1 NAA resulted in 90 % induction of SE structures at 30 d of culture period. Histological observation exhibited development of pro-embryo to form completed embryo. The pattern of SEs development started from embryogenic callus to form pro-embryo, followed by globular phase at 10 d of culture. Globular embryo elongated to form suspensor at 20 d of incubation period, and completed embryo. Regeneration of SEs into complete plantlets was attained on the half-strength MS medium without addition of any plant growth regulator (PGR). Based on the results of the present study, it can be concluded that half-strength MS medium supplemented with NAA 0.01 mg L-1 and BAP 0.05 mg L-1 is the best medium for induction of SEs from embryogenic calli.