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

Abstract

Differentiation among populations of the Iranian Teucrium polium L. was analyzed on the basis of morphological and phytochemical variab ility, to evaluate the level and distribution of diversity among four distant popula tions from arid, semi-arid, and sub- humid regions of Fars Province. Morphological analy sis included 11 characters related to the plant, leaf, and stem morphology. Analyses of v ariances and clustering were done to establish the variability and significance of morph ological differentiation. The morphological analysis of plants from the studied p opulations confirmed that the species belonged to malacophyllous xeromorphic species and were distinguished by stable conservative xeromorphic characteristics. Morpholog ical variation was correlated with ecological conditions at the site of origin and the re 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 capilla ry 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 det ected in oil samples from arid populations. All oil samples, however, were dominat ed by hydrocarbon compounds. The relatively low morpho-chemical diversity in the pop ulations indicates that the maintenance of their evolutionary potential is at r isk if population sizes are not maintained and if there is no protection of the hab itats. Keywords: Essential oil, Medicinal plant, Morphology.