عنوان مقاله [English]
Introduction: Medicinal plants are rich sources of the main active substances in many drugs. Although the production of secondary metabolites is controlled by genes, their production are considerably influenced by environmental conditions, so that environmental factors cause changes in the growth of medicinal plants as well as the amount of active substances. In different habitats, physiological, morphological and genetically variations are seen in populations of species. These variations are created in response to contrasting environmental conditions. Studies of population in many plant species regarding to the pattern of variation have showed the occurrence of localized populations which adapted to the particular ecological conditions of their habitat. Iran as a center of diversity of Stachys houses about 35 species. The majority of species prefers alpine and subalpine habitats and grows under various ecological conditions in habitats like rocky places, mountain steppes, and stream banks or sometimes in forests. S. inflata Benth. is a medicinal plant from Lamiaceae family which is used extensively in folk and traditional remedies to treat infection, asthma, rheumatism and other inflammatory diseases.
Materials and Methods: This study was conducted to evaluate the morphological and phytochemical diversity of seven populations of S. inflata Benth. from different districts of Hamedan province in 2017. Traits such as plant height, stem diameter, leaf length and width, fresh and dry weight of floral branch, inflorescence length, fresh and dry weight of flower, essential oil percentage and phenol and flavonoid content were measured. In order to investigate physical and chemical properties of soil, soil samples were collected from a depth of 30 cm. Then they were transferred to the soil laboratory. Plants samples were collected in flowering stage and were dried in 25-30 °C. They were stored in envelopes in 22±3 °C away from the sun. For extracting essential oil, 50 gr of shoots were milled and then mixed with distilled water. This process lasted for three hours. Main components of essential oil were identified and determined by gas chromatography. The grouping of populations based on morphological and phytochemical traits was done by cluster analysis. The correlation between the elevations of studied areas above the sea level and soil properties was also done by Pearson method.
Results and Disscution: The results showed that the highest essential oil content was related to Avarzaman, Aznaveleh and Koohani populations (0.2%) and the lowest amount was obtained from Asadabad (0.11%). Although 22 compounds were identified in the essential oil, there was a great deal of variation in the percentage and type of components of the essential oil in the studied populations. The main components of essential oil were Spathulenol (26.25%), Octanol acetate (14.03%), Germacrene D (13.96%), Incensole acetate (13.41%), Bicyclogermacrene (10.66%) and Phytol (9.52%). Avarzaman population had the highest total phenol (141.9 mg GAE/gr) and flavonoid content (109.4 mg routine/gr) and the lowest content of phenol (86.9 mg GAE/gr) and flavonoid (68.8 mg routine/gr) was related to Asadabad and Koohani populations respectively. Avarzaman had the highest plant height (47.2 cm) and was significantly differed with other populations. The highest dry weight of floral branches (1.16 mm) was related to Asadabad population that was not significantly differed with Aznaveleh and Avarzaman population and the lowest dry weight of floral branch (0.57 mm) was observed in Koohani population. There was a significant negative correlation (-0.86) between the height of the studied habitats and the level of phosphorus in these areas. According to the morphological traits dendrogram analysis, seven studied populations were divided into two main groups. The populations of Avarzaman, Ekbatan, Ghazi Khan, Aznaveleh and Asadabad were in group A and Koohani and Gammasiab populations were in group B. Based on phytochemical traits dendrogram analysis, the populations of Ekbatan, Ghazi Khan, Asadabad, Koohani and Gammasiab were in group A and Avarzaman population was in group B.
Conclusion: In this study, the highest amount of essential oil content was obtained from populations which were collected from areas with the lowest elevation above the sea level. The soil of these areas had more phosphorous content. Therefore, the environmental factors as well as genetic factors have contributed in creating diversity in morphological and phytochemical characteristics of this plant.