Role of Growth Regulators in Callus Establishment and Differentiation in Pluchea lanceolata (Dc.) C.B. Clarke

A protocol for callus establishment and differentiation in medicinally potent plant, Pluchea lanceolata has been developed by regulating the auxin-cytokinin ratio in basal media, source of explants and physiological state of the tissue in culture. Among the various explants (leaf/shoot tip/nodal segment) tried, leaf explants proved to be the best. The ideal medium for callus induction and establishment was MS medium supplemented with NAA (1.0 mg/l) in combination with BAP (0.5 mg/l). Maximum number of shoot buds (36.6 + 0.67) through callus differentiation was achieved on MS medium supplemented with BAP (1.0 mg/l) and Kn (1.0 mg/l). Elongation and further development of shoot buds into shoots (30.0 + 0.40) was achieved on MS medium fortified with BAP (0.25 mg/l) and Kn (0.5 mg/l). Histological study of callus showed the unorganized, loosely arranged, parenchymatous mass of cells while regenerable callus showed well-arranged shoot apices and leaf primordia. The intensity of peroxidase isozymes was appreciably higher in in vitro tissue (non-differentiating callus) as compared to in vivo tissues.