Effects of plant growth regulators on rooting of four rhizomatous medicinal plants of central Himalaya

Angelica glauca Arnebia benthamii, Rheum emodi and Pleurospernuim angelicoides are high value rhizomatous medicinal plants of the Himalayan region. All these species are used as spices and have medicinal value. Their ex-situ conservation through vegetative propagation using different plant growth regulators (PGR) were examined. lndole-3-butyric acid (IBA) and Indole-3-acetic acid (IAA) at different concentrations (0.5, 1 and 1.5 mM) were used for rooting in two, three and four transversely segmented pieces of rhizome of A. glauca, A. benthamii, R. emodi and P. angelicoides. Pleurospermum angelicoides gave the highest (95.8%) rooting with (0.5 mM) IBA treatments followed by (91.6%) with (IBA 1 mM) treatment in two pieces. A. benthamii showed highest rooting (90.8%) when treated with 0.5 mM in IBA followed by (84.2%) in IAA 0.5 mM for the two pieces. A. glatica showed the highest (85%) rooting when treated with IBA 0,5 mM in three pieces followed by (81%) in IBA 0.5 mM in two pieces. R. emodi showed the highest (96.6%) rooting in IBA 1.5 mM followed by (94.4%) when treated with IBA 1 mM in two pieces. The present study highlighted that lower concentration of IBA improved rooting percentage of all the four species compared to IAA, even in control. IBA at lower concentration is cost-effective and thus highly recommended for mass propagation of these endangered species of Himalaya.