Direct multiple shoot induction and plant regeneration from dormant buds of Codonopsis pilosula (Franch.) Nannf.

Abstract

An efficient and reproducible protocol for in vitro plant multiplication system via direct organogenesis from dormant buds of Codonopsis pilosula Nannf was developed. Multiple shoots were induced at a frequency of 75% after nine weeks on Murashige and Skoog (MS) medium supplemented with BAP (1.0 mg/l), NAA (0.5 mg/l), 3% sucrose and 0.7% agar. Approximately, 15 to 18 shoots were formed at the base of each dormant bud. Higher concentrations of BAP and NAA resulted in callus formation. Further development of shoot elongation and multiplication were also studied. Well-grown shoots of 2.8 cm height and 3.8 proliferation coefficient were achieved by sub-culturing on MS medium supplemented with 0.2 mg/l BAP and 0.05 mg/l IBA. At higher concentrations, BAP (0.5 mg/l) promoted higher shoot proliferation coefficient (4.2); however, it negatively affected shoot elongation. Further, low NAA concentration was beneficial to shoot proliferation. All in vitro-derived shoots measuring 2.5 to 3 cm in length, rooted when grown on ½MS (half of all MS elements) basal medium containing 1.5 mg/l IBA within 3 weeks, 100% of shoots developed roots and test-tube seedlings grew stout.

Key words: Codonopsis pilosula, dormant bud, direct organogenesis, multiple shoot, shoot elongation, rooting.