Micropropagation and composition of essentials oils in garden thyme (Thymus vulgaris L.)

Abstract

Thymus vulgaris L. is an important aromatic plant, because of the synthesis and production of its essential oils for the pharmaceutical and cosmetic industries. In this study, we developed a micropropagation protocol for T. vulgaris 'Sloneczko' and evaluated the potential of micropropagated plants for essential oil production with industrial application. The seeds were soaked for 10 min in 10% sodium hypochlorite (NaOCl) solution. Then, each seed was put into a 20 ml test tube filled with 5ml of Murashige and Skoog (MS) medium. Half of the cultures were subjected to light intensity which was maintained at 40 μEm-2s-1, and the other half was cultured in the dark. Shoot explants were multiplied in vitro using MS medium supplemented with BAP, 2iP or KIN. The results obtained indicate that the cytokinin which had the most positive impact on plant development at the multiplication stage was 5 mg dm-3 2iP. Single-node fragments of shoots cultured on MS medium without plant growth regulators were transferred to MS medium supplemented with IAA, IBA and NAA at concentrations of 0.2, 0.5, 1 and 2 mgdm-3. The best rooting of shoots was obtained on MS medium supplemented with 2 mgdm-3 IBA. The essential oils obtained by hydrodistillation in Deryng and Clevenger apparatus from in vitro shoot cultures of T. vulgaris L. were analysed using gas chromatography-mass spectrometry (GC-MS). Analysis revealed the presence of 54 components represented mainly by oxygenated monoterpenes (56.81-57.28%) and monoterpene hydrocarbons (31.90-33.72%). Among identified constituents, the most abundant were thymol (33.37-34.05%), γ-terpinene (11.62-11.91%), p-cymene (9.81-10.07%), carvacrol (5.63-5.96%), carvacrol methyl ether (3.86-3.87%) and linalool (3.16-3.36%).