The Essential Oils and Glandular Hairs in Different Chemotypes of Origanum vulgare L.

Abstract

Leaves and flowers of four chemotypes of Origanum vulgare L. were examined for the main components of their essential oil and for the types and distribution of their glandular hairs. Two varieties have high phenol content, one thymol and the other carvacrol, in their essential oils; one has a moderate thymol content and the fourth has a low phenol content and a high alcohol content. The percentage of essential oil and the number of peltate hairs were higher in the flowers than in the leaves, the highest being in the flowers of a chemotype with a high phenol (thymol) concentration. While there were no differences in structure of the peltate and two types of capitate hairs between chemotypes, the density of the peltate hairs varied and appeared to be correlated with the total essential oil content.