Effects of ecological factors on essential oil components of several genotypes of Thymus daenensis Celak using ordination technique

Thymus daenensis Celak is one of the Iranian endemic plants. Since this species is one of the most valuable medicinal plants in the central Zagros region, extra-human exploitation has put it at risk of extinction. Ordination technique is one of the methods showing the relationship between plant and environmental variables. In order to study the effects of ecological variables on essential oil components, eight growing regions of Thymus daenensis in Isfahan province were identified and after collecting the aerial parts of plant materials, the essential oil was extracted and their components were detected. Twenty four bio-climatical, edaphical and topographical factors in each habitate were collected for ordination analysis. Results showed that elevation, mean temperature of the wettest season, isothermality, precipitation of the wettest season, annual precipitation, precipitation of the driest season and annual temperature range, clay, gravel, organic matter, available nitrogen and potassium were the most effective variables on the essential oil components. Thymol content as the main component in the essential oil was affected by annual temperature range, elevation, and slope. Soil sand percentage and the mean temperature of wettest quarter were the most effective variables on carvacrol. The result of this study could have valuable role in Thymus daenensis cultivation management in nature or farm regarding to its chemical components needed in the medicinal and hygienic industries.