Establishment of in vitro fast-growing normal root culture of Vernonia amygdalina - a potent African medicinal plant

Fast-growing normal root culture of Vernonia amygdalina, a potent African medicinal plant was established from leaf explants of in vitro raised shoot induced from the stem nodal segments on murashige and skoog (MS) medium containing 0.5 mg l-1 6-benzylaminopurine (BA) in combination with 0.5 mg l-1 naphthalene acetic acid (NAA). In vitro raised plantlets were maintained on MS agar medium and sub cultured at 4 weeks interval and used as leaf explant source. Explants were cultured on halfstrength MS medium supplemented with different concentrations of Indole-3-acetic acid (IAA), indole-3- butyric acid (IBA) and NAA. Basal medium supplemented with IBA at 0.25 and 2.0 mg l-1 and under 16 photoperiod condition favoured induction of the longest root (2.7 ± 1.1 cm) and highest number of roots/explant (38.3 ± 1.1) respectively. After 6 weeks well established roots were separated. Fresh root tissue, in amount of a 100 mg were cultured in 50 ml full-strength MS liquid medium supplemented with 2.0 mg l-1 IBA and under continuous agitation (80 rpm). The biomass of root culture was increased to 2.1949 g after 5 weeks of culture. The root culture was maintained up to 6 weeks. The protocol developed in this study provides a basis for adventitious root induction and for further investigation of medicinally active constituents of this elite medicinal plant.