Plant development and synthesis of essential oils in micropropagated and mycorrhiza inoculated plants of Origanum vulgare L. ssp. hirtum (Link) Ietswaart

Biomass production of micropropagated oregano was induced by inoculation with the fungus Glomus viscosum. The effects of arbuscular mycorrhizal (AM) symbiosis on morphological and metabolic variations of regenerated oregano plants were investigated at different growth stages. AM greatly increased parameters such as plant leaf area, fresh and dry weight, number of spicasters and verticillasters in infected plants. An increase of the gland density, especially on the upper leaf epidermis, was also observed following the physiological ageing of the tissues. The in vitro plants of O. vulgare ssp. hirtum described in this study provided a qualitatively and quantitatively good source of essential oils that have a chemical profile comparable to that of the control mother plants with carvacrol as the main compound.