Geological substrate-related variability of Teucrium montanum L. (Lamiaceae) essential oil

This study aimed to determine the qualitative variability of essential oils of mountain germander - Teucrium montanum L. (Lamiaceae) at the population level, depending on the type of geological substrate. Ten samples of essential oils originated from aerial plant parts of populations from calcareous and ten from serpentinite were tested by GCxGC-MS method. The obtained results showed that the serpentinite populations have more than 3 times higher essential oil yield than calcareous populations. Based on the average values for the relative percentage amounts of T. montanum essential oils, it was shown that the sesquiterpenes (34.89%) are the main compounds in analyzed essential oils. Population from calcareous habitats synthesize twice as many aliphatic hydrocarbons than populations from serpentinite habitats, while populations from serpentinite habitats synthesize twice as much mono-and sesquiterpenes. The compounds with highest relative percentage amounts in calcareous populations was the hydrocarbon tetracosane (9.02%), while in serpentinite populations it was oxygenated sesquiterpene, limonen-10-ol (4.81%). Compounds which were only detected for calcareous populations are: dodecane and isophytol, while for serpentinite populations are: 3-caren-2-ol, carvone oxide and pyronene. The obtained results indicate a significant influence of the habitat geological substrate on the qualitative characteristics of the T. montanum essential oil. Differentiation of calcareous and serpentinite populations into two distinct groups based on the essential oil composition indicate the significant presence of specific chemotypes developed by the influence of various edaphic characteristics.