The effect of environmental factors on plant vegetation is different. Therefore, it is necessary to evaluate role of these factors in medicinal plants growth, development and essential oil. This study was performed to investigate the effect of factors on qualitative and quantitative variations of the essential oil of Verbascum songaricum in its habitats in central Zagros Mountains, Iran in 2012. V. songaricum aerial biomass was collected in flowering stages from four rangeland sites in Isfahan (Dareh Hose, Ghahiz, Ghaleghadam, Semirom) and one site in Kohgiluyeh, and Buyerahmad (Dena) provinces, Iran. The samples were dried in open air and their essential oils were extracted through digestion method. Gas Chromatography Mass Spectroscopy (GC-MS) was used to identify essential oil composition as Alcohol, Hydrocarbon, Amin, Acid, Ester and Ketone of species in five sites. The most important environmental factors such as climate, and physiographic, soil physical and chemical properties were determined. In order to investigate the relationship between environmental factors and plant essential oil, Ordination analysis was performed using Redundancy Analysis (RDA). The results of correlation analysis indicated that the most important environmental factors affecting the essential oil were annual rainfall (r=0.86), frozen days (r=0.86), Aridity index (r=0.86), Altitude (r=0.86), gravel (r=0.74), nitrogen (r=0.78), organic matter (r=0.62) and soil texture (r=0.68). Results showed that there was an increase in essential oil production in V. songaricum under semi-arid cold climate, uplands, higher precipitation, relatively light texture and fertile soil. According to RDA analysis, two habitats were identified. The first habitat was more appropriate for essential oil production of V. songaricum (Dareh Hose, Semirom and Dena) in comparison with the second one (Ghahiz and Ghaleghadam). As a result, the first habitat was considered as a suitable natural place for the cultivation and domestication of V. songaricum. پرونده مقاله

Salicornia herbacea is a sensitive species to seed shedding. In order to determine the effect of harvesting date on seed shedding, seed germination and seed oil production, an experiment was conducted in Gomishan Lagoon rangelands, Golestan province, Iran. Seed samples were harvested in twenty 1 m2 plots in 12 times since Nov 6th as the initial date of seed setting until Dec 21st as the final stage of seed maturity in 2019. Sampling was first carried out once a week and increased to every two days at the end of sampling dates. In each plot, the number of shrubs, visual evaluation of plant color changes from green to red, and brown coupled with the weight of the spilled seeds were recordedon each sampling date. Then, the required amount of seeds was randomly taken for the germination test and oil extraction. The obtained data were analyzed using PAST software. The results of analysis of variance showed significant differences between sampling dates on seed germination and oil percent (p <0.05). The highest and lowest germination rates with average values of 91% and 98% were obtained in the initial and final stages of harvesting, respectively. Also, the highest and lowest oil yield with average values of 19% and 16% was obtained in the middle and final stages of seed maturity. The results of multivariate analysis showed significant relationships between the seed shedding and plant color (green, red and brown) (p <0.05). According to the results, among the visible plant traits, the brown color (dryness) in up to 60% of the plants had the lowest shedding rate and was recommended as a good indicator for determining the suitable date to harvest Salicornia herbacea seeds. پرونده مقاله

Medicinal plant species constitute a considerable part of the flora in Iran and play a major role in the composition of plant communities. Therefore, it is necessary to recognize the factors leading to the establishment and distribution of vegetation. For data sampling (2012), land units were specified. The plot size was determined using minimal area method and number of plots was determined by statistical methods according to the changes in vegetation cover. 120 1 m2 plots were selected and within each plot, the presence and absence of species and cover percent were estimated. The soil samples were taken in each plot in (0-30 cm) depth. Data were collected and analyzed using Principle Component Analysis (PCA). Results indicated that the first three axes explained the total variation. The variables of altitude, OM, N, pH, and sand had significant correlations with the first axis and explained the 60% variation. For the second component, topographic properties and EC were more important traits and explained the 29% variation. These two components explained the 89% vegetation cover variation in Ghorkhud region as G1 (Eryngium bungei-Asperula arvensis) and G2 (Conium maculatum-Acantholimon pterostegium) types were grown in sandy soils (low OM, N, pH and high EC) coupled with high altitude and slope, G3 (Asperula arvensis-Cichorium intybus) type had a higher adaptability with sandy soils (low OM, N and pH) coupled with lower EC, higher altitude and lower slope and G4 (Artemisia sieberi-Convolvulus arvensis) type tended to be established in clay soils (lower sand% and higher OM, pH and N) and lower altitude. پرونده مقاله

One of the main objectives of ecosystem management is to preserve the speciesdiversity. Many researchers regard higher species diversity as the stability of ecologicalsystems. The aim of this study is to investigate the stability and relationships betweentopographical factors with diversity indices in Ghorkhud mountainous rangeland innorthern Khorasan province, Iran. For data sampling (2012), land units were specified.Floristic list was prepared and minimal area was determined based on the nested plot(Braun-Blanquet method). 120 plots of 1m2 were selected and within each plot, thepresence of species and cover percent were estimated. For data analysis and meanscomparison of species diversity between the study sites, One-way ANOVA and Duncantests were used. The species diversity was investigated using numerical indices andstability of the habitat was determined using parametric indices. The results showed thatspecies diversity was decreased due to the increased altitude. Diversity indices wereincreased by the increased slope percent. Also, eastern slopes had the most diversity ascompared to the other driving directions since the communities with high and lowdiversities generally follow the Log-Normal and Geometric models, respectively.According to our results, the areas with light slopes, middle altitudes and north and westdirections followed the Log Normal distribution which had the most stable levels. It wasconcluded that the area with Log-Normal model represents a relatively stable communitieswith medium to high species richness. پرونده مقاله

Abstract. The purpose of this study was to investigate the effects of topographical factors on the classification of grassland plant communities in the rangelands of Ghorkhud, Northern Khorasan Province, Iran. For sampling, land units were specified. A floristic list was prepared using minimal area method based on the nested plot (Braun-Blanquet method). 116 10m2 furrows were selected. Within each furrow, the presence and cover percent were estimated. On the basis of Braun-Blanquet classification method, cover percent of each species was ranked and the representative matrix was established. Vegetation was characterized by the means of Braun-Blanquet classification method using TWINSPAN level 2. To determine the relationships between vegetation and effective topographic factors, a Canonical Correspondence Analysis (CCA) method was used. Results showed that the region's vegetation was divided into four plant communities including Stipa barbata-Festuca ovina, Festuca ovina-Agropyron trichophorum, Stipa hohenackeriana-Festuca ovina and Agropyron cristatum-Stipa barbata, respectively. Based on results of CCA, the first and second axes (Eigenvalue=0.39, 0.29 ) were accounted for 50.2 and 37.7% variations, respectively and totally, the first two axes were accounted as 82% of total variation concerning the environmental factors such as aspect with the first axis and elevation and slope with the second axis. پرونده مقاله