Effect of Mutagens on the in Vitro Adventitious Shoot Growth and Bacoside a Accumulation in Bacopa Monnieri (l.)

Mutations were induced in tissue cultured raised Bacopa monnieri (L.) plantlets by treating in vitro derived leaves with gamma rays at (γ – rays) dose rate of 0, 10, 20, 40 and 80 gray (Gy) and 0.5% of ethyl methanesulphonate (EMS) at 0, 0.5, 1.0, 1.5, 2.0 and 2.5 hours (h). Xantha mutants were observed with γ rays at 10, 20 and 40 Gy. All the leaf explants treated with 80 Gy were either necrotic or irregenerable. Both γ and EMS treatment exhibited a reduction in survival rate, number of adventitious shoots, fresh weight and dry weight (DW). The γ rays doses at 10, 20 and 40 Gy induced mutation in Bacopa monnieri leaf explants and five lines were obtained with increased in the bacoside A content. The lines obtained are D15 (40 Gy) which produced maximum amount of bacoside A (22.567 mg g DW) followed by B11 (10 Gy), C18 (20 Gy), D17 (40 Gy) and B6 (10 Gy) lines which accumulated 21.051, 19.320, 17.163 and 14.133 mg g DW respectively compared with control (13.750 mg g DW). The leaf explants treated with EMS did not show any significant increase with respect to the bacoside A content.