Essential Oil Variability of Juniperus oxycedrus s.l. Taxa in Southeast Europe - a Chemophenetic Approach.

The essential oil composition of 14 natural populations of two Juniperus oxycedrus s.l. taxa (J. deltoides and J. macrocarpa) was studied in southeast Europe. These two genetically close taxa have different distributions. Essential oils were dominated by monoterpene hydrocarbons (33.8-64.1%), although sesquiterpenes and diterpenes were also present in high concentrations in several populations,. Limonene, ⍺-pinene, manoyl oxide, and cedrol were the most abundant compounds, though EO profiles differed between taxa. In almost all samples of J. macrocarpa, ⍺-pinene was the most abundant compound. Most individuals of J. deltoides had one of the three chemotypes- ⍺-pinene, limonene and limonene/⍺-pinene, though six others were detected in a smaller number of individuals. Multivariate statistics examined variability with population, species, and environmental characteristics. The most common chemotypes of J. deltoides allowed the separation of populations along the climate line/proximity to the Mediterranean Sea, with ⍺-pinene being more common in continental populations. In addition, multivariate statistical analysis based on leaf EO composition showed a clear separation between Juniperus deltoides and J. macrocarpa populations from southeast Europe. This study emphasizes the importance of large-scale chemophenetic studies.