Because, previous studies (e.g. Radušienė and Janulis, 2004) showed that most of the raw material of commercial medicinal and aromatic species yet being collected from spontaneous populations in many parts of the world. Although, samples of some medicinal and aromatic herbs are cultured.
These populations were selected from different regions of the country; therefore some degrees of infraspecific variations were expected. These types of variations are seen in different genus as well as families. Lukovic et al. (2009) stated that plants respond to environmental variations, particularly to water availability through morphological, anatomical and biochemical adjustments that help them cope with such variations. for example, Pereira et al.…show more content…
Moreover, Tehran and Polor populations were far from each other. It seems that these populations had different taxonomic rank from the rest or at least were ecotypes.
The essential oil compositions and their percentages differed between the studied populations. The major parts of oil highly varied between the samples. Various studies (e.g. Figueiredo et al., 2008; Lakuŝić et al., 2012) proved that populations of the same species collected from different habitat have diverse essential oil composition. Because, the essential oils biosynthesis is under the influence of many abiotic and biotic factors. Formisano et al., (2015) stated the plant phytochemical composition is strongly influenced by the environment condition, and this is particularly true for medicinal herbs.
Sesquiterpene hydrocarbon, oxygenated hydrocarbon, monoterpene hydrocarbon and oxygenated monoterpene constituted major parts of essential oil. The mounts of these compounds widely differed between the examined samples; therefore, the profile of essential oil compositions differed between the examined samples. Glynn et al., (2007) reported variations of terpene content with environmental stress. The growth-differentiation balance hypothesis postulates that there is a physiological trade-off between growth and secondary metabolism.
These variations were