In vitro conservation of Plumbago indica - A rare medicinal plant

Abstract

Present work has been conducted on in vitro conservation of a rare medicinal plant, Plumbago indica, through storage of germplasms derived from micropropagated progenies of the species. Direct regeneration of axillary shoots and their multiplication have been optimized using BAP at a concentration of 2.0 mg/l in MS with 3% sucrose. Plantlets with profusely growing roots, induced by 1.0 mg/l putrescine have been transferred successfully to natural environment as evident from their high survival rate. In vitro storage of P. indica has been developed by (1) reduced growth culture of shoot apex explants for prolonged period without periodic transfer and (2) by preserving encapsulated in vitro generated propagules (artificial seed) for a short term period. Combined application of mannitol (3%) and BAP (2.0 mg/l) resulted in significant reduction in growth rate. After 12 months of storage, cultures survived with 100% success by re-growing in regeneration medium. The alginate-coated beads, made by encapsulating small groups of propagules in each are excellent storable germplasm units, which on germination gave rise to 4-6 plantlets / bead on average on or before 3 months storage at tissue culture room temperature (22°C - 24°C) in absence of light and showed high survival ability. The report on in vitro conservation of this important medicinal plant germplasm may open up new possibilities in this area.