Effect of coconut water and cytokinins on rapid micropropagation of Ranunculus wallichianus Wight & Arnn—a rare and endemic medicinal plant of the Western Ghats, India

Abstract

Ranunculus wallichianus is a rare medicinal plant endemic to Western Ghats, India. Nodal explants were inoculated on MS medium with 1.0 to 5.0 mg L−1 of 6-benzyladenine (BA), kinetin (KIN), or thidiazuron (TDZ) resulting in a low percentage of shoot regeneration. Coconut water (CW) was added to MS medium containing the above mentioned cytokinins to promote in vitro plantlet growth. Multiple shoots were regenerated on half-strength Murashige and Skoog (MS) medium containing 1.0 to 5.0 mg L−1 BA, KIN, or TDZ in combination with 5%, 10%, and 20% CW. The highest percentage of shoot multiplication was observed from cultures incubated on half-strength MS medium supplemented with 3.0 mg L−1 TDZ in combination with 10% CW. The cut ends of well-elongated shoots were transferred to medium containing 0.5 to 3.0 mg L−1 indole-3-acetic acid (IAA) or indole-3-butyric acid (IBA) to induce in vitro root induction. Half-strength MS medium with 2.5 mg L−1 IBA and 250 mg L−1 activated charcoal shows high frequency of root formation. The well-rooted plantlets were transferred to pots for hardening with survival rate of 93% after 30 d. The present work indicates the addition of CW with the cytokinins in half-strength MS medium is suitable for rapid micropropagation of R. wallichianus.