Abstract
THE CURRENT study investigates the effect of growth regulators on micropropagation, callus induction and callus flavonoid content of Rumex pictus Forssk; an endangered medicinal plant. Various combinations of kintin (KIN), 6-benzylaminopurine (BAP), Thidiazuron (TDZ) and indole-3-butyric acid (IBA) were used for micropropagation from shoot tip explants. Murashige and Skoog (MS) medium containing 2mg L-1 BAP was the best for micropropagation where shoot formation frequency was 70% with 12.6 shoots/explant. The highest root formation frequency resulted on half-strength MS medium fortified with 2mg L-1 naphthalene acetic acid (NAA) or 1 mg L-1 IBA. One mg 2,4-dichlorophenoxyacetic acid (2,4-D) combined with 0.4mg L-1 BAP induced the highest callus mass production from the investigated explants, particularly 1st foliage leaf that was the best explant for callus induction and proliferation. The accumulation of flavonoids in callus was diminished by BAP but enhanced by increasing 2,4-D concentration in culture medium. To our knowledge, this is the first report of micropropagation and callus induction of this endangered medicinal plant which will help in its rapid mass production, conservation and in vitro production of secondary metabolites.