Journal of Chemical Ecology

, Volume 29, Issue 4, pp 859–880

Qualitative and Quantitative Variation in Monoterpene Co-Occurrence and Composition in the Essential Oil of Thymus vulgaris Chemotypes

Authors

    • Centre d'Ecologie Fonctionnelle et Evolutive, CNRS
  • Jean-Claude Chalchat
    • Laboratoire de Chimie des Huiles EssentiellesUniversité Blaise Pascal de Clermont Campus des Cézeaux
  • André Michet
    • Laboratoire de Chimie des Huiles EssentiellesUniversité Blaise Pascal de Clermont Campus des Cézeaux
  • Yan B. Linhart
    • Department of Environmental Population and Organismic Biology N122 Ramaley
  • Bodil Ehlers
    • Centre d'Ecologie Fonctionnelle et Evolutive, CNRS
Article

DOI: 10.1023/A:1022927615442

Cite this article as:
Thompson, J.D., Chalchat, J., Michet, A. et al. J Chem Ecol (2003) 29: 859. doi:10.1023/A:1022927615442

Abstract

Thymus vulgaris has a chemical polymorphism with six different chemotypes that show marked spatial segregation in nature. Although some populations have a single chemotype in majority, many have two or three chemotypes. In this study we analyze the quantitative variation among T. vulgaris populations in the percentage of oil composed of the dominant monoterpene(s) for each chemotype. In general, phenolic chemotypes (thymol and carvacrol), which occur at the end of the biosynthetic chain, have a significantly lower proportion of their oil composed of their dominant monoterpene than nonphenolic chemotypes (geraniol, α-terpineol, and linalool). This is due to the presence of high amounts of precursors (γ-terpinene and paracymene) in the oil of phenolic chemotypes. The essential oil of the nonphenolic thuyanol chemotype has four characteristic monoterpenes that together make up a lower proportion of the oil than the single dominant monoterpene of the other nonphenolic chemotypes. For all chemotypes, the percentage composition of the dominant monoterpene decreased significantly at sites where the chemotype is not the majority type. This decrease is correlated with a significant increase in either the proportion of the two precursors for the thymol chemotype or the monoterpenes characteristic of the other chemotypes at the site. The latter result suggests that a plant with dominant genes is responsible for the production of different monoterpenes can produce several molecules.

Lamiaceae Mediterranean adaptation essential oil composition monoterpene production polymorphism

Copyright information

© Plenum Publishing Corporation 2003