In vitro multiplication and ecorehabilitation of the endangered Blue Vanda

Abstract

Rapid multiplication of endangered Vanda coerulea Griff ex. Lindl. (Orchidaceae) was achieved through culture of shoot tips of mature plants, shoot tips and leaf bases of 8-month-old axenic seedlings on Mitra et al. (1976) medium supplemented with 10% coconut water, 500 mg1^-1 casein hydrolysate and a combination of 8.8 μM benzyladenine and 4.1 μM napthaleneacetic acid (NAA). Shoot tips (0.5 – 0.8 cm) cultured in both agar and agitated liquid media responded alike with direct formation of 3–12 shoot buds in 12 weeks, while callus-free formation of 3–8 protocorm-like bodies (PLBs) in 4–8 weeks was noticed in seedling leaf base segments (1.0–1.5 cm). Formation of new buds or PLBs, rapid growth of buds into shoots and emergence of shoots from PLBs occurred when the explants with proliferating buds / PLBs were subcultured in medium enriched with 35 g 1^-1 banana pulp, 30% coconut water and 1.08 μM NAA. A maximum of 70 and 100 shoots of varied length were obtained from a single shoot tip/leaf base explant after 30 weeks of culture. Rooting of shoots (3.0–4.0 cm) occurred in medium containing 35 g 1^-1 banana pulp and 1.08 μM NAA within 3–4 weeks. Rooted plants were established easily (95–100%) in community pots without hardening. The regenerated plants were cytologically stable (2n = 38). They were free from morphological, growth and flowering abnormalities. Eighty-five community potted plants were reintroduced into alien forest habitats at Ponmudi and Palode in southern ranges of the Western Ghats. They established at 70–80% rate.