“In vitro” Hedeoma multiflorum Benth propagation in response to different nutritional conditions

Abstract

An efficient protocol for in vitro propagation of Hedeoma multiflorum Benth (“Tomillo de las Sierras”) was established. To determine the effect of different medium and plant growth regulators on the growth rates and essential oil production, nodal segments from in vitro 90-days old plantlets were incubated on the following media: 1) SH (Schenk and Hildebrandt); 2) WP (Lloyd and McCown); 3) B5 (Gamborg). All the media studied were supplemented with different combinations and consentrations of growth regulators: naphtaleneacetic acid (NAA) and 6-benzyl adenine (BA). The optimal shoot length and number of nodes of the plantlets, showing no statistical difference, were obtained in WP with the addition of 2.69:0.5 μM, 0.5:0.5 and 2.69:0.05 μM of NAA:BA and in absence of these growth regulators (control). The best multiple shoot medium with no statistical difference, corresponded to SH with the addition of 0.5:2.25 μM and B5 with 0.05:2.25, 0.5:2.25 and 2.69:2.25 μM of NAA:BA. The major essential oil determined by GC/MS, were common in all the plantlets grown in all the media being pulegone (62-64%) , menthone (25-28 %) and isomenthone (2-2,3%).