Morpho-chemical Diversity among Iranian Teucrium poliumL. (Lamiaceae) Populations in Fars Province

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Differentiation among populations of the Iranian Teucrium polium L.was analyzed on the basis of morphological and phytochemical variability, to evaluate the level and distribution of diversity among four distant populations from arid, semi-arid, and sub-humid regions of Fars Province. Morphological analysis included 11 characters related to the plant, leaf, and stem morphology. Analyses of variances and clustering were done to establish the variability and significance of morphological differentiation. The morphological analysis of plants from the studied populations confirmed that the species belonged to malacophyllous xeromorphic species and were distinguished by stable conservative xeromorphic characteristics. Morphological variation was correlated with ecological conditions at the site of origin and there was a small difference between the plants belonging to arid and semi-arid populations and the sub-humid ones. Chemical analysis was performed using combination of capillary GC, GC-MS after fractionation on column chromatography. The chemical composition of their oil differed qualitatively and quantitatively between the populations. β-Caryophyllene was the major oil compound in the sub-humid and semi-arid populations, while the main compound of arid populations were farnesene-cis-b and linalool. In addition, oil samples from semi-arid and sub-humid populations contained β-bisabolene (1.6-2.2%), myrcene (0.9-1.1%), bornyl acetate (0.7-0.8%), and 3-octanol (0.6-0.8%), which were not detected in oil samples from arid populations. All oil samples, however, were dominated by hydrocarbon compounds. The relatively low morpho-chemical diversity in the populations indicates that the maintenance of their evolutionary potential is at risk if population sizes are not maintained and if there is no protection of the habitats.