Effect of liquid medium on shoots amplification, in vitro flowering and ex vitro rooting of Oldenlandia umbellata L. - A dye yielding medicinal herb

Abstract

Oldenlandia umbellata L. gains importance due to its medicinal properties and the presence of anthraquinones based natural dyes in the roots. Present study describes the effect of Murashige and Skoog’s (MS) liquid medium (full strength) on in vitro regeneration, flower bud induction and ex vitro rooting in O. umbellata. Shoot segments with 2-3 nodes (each node with 2 axillary buds) served as explants for establishment of cultures. The liquid medium augmented with 2.0 mg L-1 6-benzylaminopurine (BAP) with additives (50 mg L-1 of ascorbic acid and 25 mg L-1 each of arginine, adenine sulphate and citric acid) was effective for shoot bud induction (6.4±0.19 shoots per explant within 2-3 weeks). The shoots were further multiplied (89.3±1.07 shoots, 2-3 weeks) when the shoot clusters obtained from the culture initiation directly transferred to the full-strength MS liquid medium incorporated with 1.0 mg L-1 BAP and 0.5 mg L-1 indole-3 acetic acid (IAA) with additives. Flower buds were induced (12.0±0.15 buds per shoot) when the shoots were cultured on 1.0 mg L-1 BAP and kinetin (Kin, 6-furfurylaminopurine) and 0.5 mg L-1 of IAA at 45 µmol m−2 s−1 SFPD (Spectral Flux Photon Density) light intensity for 14/10h (light/dark) photoperiod. The adventitious roots were induced on 1/4 strength MS medium supplemented with 1.5 mg L-1 indole-3 butyric acid (IBA). Ex vitro rooting was achieved (16.0±0.53 roots per shoot) by pulse treatment of the shoots with 300 mg L-1 IBA for 2 min. The in vitro produced plantlets were acclimatized in the greenhouse and finally translocated to the in vivo conditions with 93 % success rate. This is the foremost (use of liquid MS medium) and cost-effective method for large scale multiplication of O. umbellata.