Effect of Sugars, Gibberellic Acid and Abscisic Acid on Somatic Embryogenesis in Tylophora indica (Burm. f.) Merrill

The effect of sugars, gibberellic acid (GA3) and abscisic acid (ABA) on somatic embryogenesis from inter-nodal explant-derived callus of Tylophora indica(Burm. f.) Merrill has been investigated. Embryogenic calli were produced from inter-nodal explants and the best result was achieved using Murashige and Skoog (MS) medium supplemented with 4 μmol/L 2, 4-Dichlorophenoxyacetic acid (2, 4-D). Up to 69% of such embryogenic calli differentiated into somatic embryos with an average of 25 embryos per explant (per gram of the calli) on MS medium containing 6 μmol/L kinetin (Kn). The individual effect of sucrose and glucose together with 6 μmol/L Kn was evaluated. There was a significant difference among the concentrations of sugar and among the kinds of sugar tested in somatic embryogenesis. Sucrose at 200 mmol/L with 6 μmol/L Kn gave rise to a maximum embryogenesis (71%) with an average of 49 embryos per explant. However, glucose together with 6 μmol/L Kn or a combination of glucose, sucrose, and 6 μmol/L Kn reduced the percentage of embryogenesis culture and the number of embryos per explant. The presence of GA3 and ABA at particular concentrations promoted somatic embryogenesis in T. indica. The addition of 10 μmol/L GA3 into the 200 mmol/L sucrose-containing medium gave a 98% embryogenesis response with an average of 51 embryos per explant. Somatic embryogenesis was significantly enhanced by the addition of 2 μmol/L ABA to 200 mmol/L sucrose-containing medium. On this medium, 95% embryogenesis with an average of 44 embryos per explant was observed. The study reported here indicates that 200 mmol/L sucrose with 6 μmol/L Kn, 200 mmol/L sucrose with 10 μmol/L GA3, and 200 mmol/L sucrose with 2 μmol/L ABA significantly improved somatic embryogenesis in T. indica, whereas glucose alone or in combination with sucrose had an inhibitory role. The embryos obtained developed normally and transformed into plants easily.