r. yari

The presence of plant species in each region is influenced by the environmental and biological factors of that region. Therefore, to establish the coverage and distribution of plant species and the factors affecting their growth and development, it is necessary to research the ecological requirements of the species and the environmental characteristics of the studied area. This information can be used for planning and implementing basic management plans for the restoration and modification of habitats and the protection of water and soil resources. This research aims to identify the habitat conditions of Prunus scoparia (Spach) C.K.Schneid.

This research was conducted in Razavi and South Khorasan provinces across six habitats: Qaen, Bajestan, Ferdows, Khaf, Bardaskan, and Sarayan. In each representative area, a site was selected, and three transects of 100 meters were established, each with a distance of 20 meters. Along each transect, 10 plots of four square meters were established (a total of 30 plots in each habitat). In each plot, the percentage of canopy cover, density of a single plant species, litter percentage, and bare soil percentage with pebbles were determined. Additionally, for each habitat, two soil samples were collected from the beginning and end of each transect, resulting in a total of 36 soil samples. The soil texture, electrical conductivity, saturation moisture, pH, total nitrogen, phosphorus, potassium, sodium, calcium, magnesium, chlorine, lime, organic carbon, and organic matter were analyzed using conventional methods. After collecting all the climate, soil, topography, and vegetation data related to the six habitats of wild almond in Khorasan province, the scope of the ecological expansion of the studied species based on the studied factors was first determined. Then, using principal component analysis (PCA), the environmental factors affecting the distribution of wild almond species were identified.

The results showed that the Ferdows habitat exhibited the highest percentage of vegetation cover, while Bardaskan had the highest canopy cover percentage, density, and mean height for wild almond. The lowest percentage of vegetation cover, canopy cover, and density of the species was found in Bajestan, and the lowest mean height of the species was recorded in Khaf. Soil physical properties, such as soil texture components including the percentage of clay, sand, slope, and calcium, showed the largest contribution to explaining the variance of axis 1 and are more important than soil chemical properties. In the Bardaskan habitat, calcium and slope had a positive effect on the distribution of wild almond, but the percentage of clay showed a negative effect. Organic carbon is effective in the species distribution in this habitat. Altitude and rainfall are effective in the distribution of wild almond in Qaen. In general, clay, calcium, slope, sand, and maximum temperature play the biggest role in the distribution of the species in all the studied areas. There are many variations in the soil properties of the habitats. The two habitats of Khaf and Bardaskan are similar to each other in terms of soil characteristics, and wild almond is distributed in these habitats with high slopes and a high percentage of sand and calcium. In general, considering all the climatic, soil, and altitude characteristics, wild almond habitats are placed in three clusters. Khaf and Bardaskan habitats were in the first group, Sarayan and Bajestan habitats were in the second group, and Qaen and Ferdows habitats were in the third group.

The range of distribution of wild almond in the studied areas was around 1480 to 1700 meters above sea level, generally in southern directions, with slopes ranging from 10% to 66%, and annual rainfall between 130 to 187 mm. The soil texture of the habitats is loamy to sandy-loam, and the soil is non-saline. Among the studied factors, soil calcium, soil texture, slope percentage, and maximum temperature had the most significant effects on the distribution of wild almond in the studied areas. Considering the distribution of this plant in a wide range of environmental conditions, including climate, physiography, and soil, and its positive effect on controlling soil erosion on slopes, it is recommended to cultivate this species in degraded mountainous areas.

Aiming to understand the habitat conditions of Prunus chorassanica (Pojark.) A.E.Murray as an endemic shrub species of Iran, this study was conducted in Khorasan Razavi Province. To measure the canopy coverage percentage and density of plant species in the three studied sites located in Dargaz County, three transects of 100 meters were established. Along each transect, a 5 m2 plot was established every ten meters and sampling was done by systematic random method. Also, the ecological conditions of the species growth and distribution; including climate, topography and edaphic characteristics of the sites were investigated. The canopy cover of P. chorassanica in the three studied sites were 7.87 to 11.7% and the density were between 50 to 75 tree per ha. In the shrub's sites, 34, 38.5 and 27.5% of the soil was sand, silt and clay and the desired soil texture was loam. The average pH and electrical conductivity of the soil are equal to 7.73 and 0.8 dS/m, respectively. This species grows and spreads in altitudes above 2000 meters and on slopes between 30 and 55%, generally in the northern direction. Considering the value of this species, in the form of action for protection outside the main site, it is necessary to collect the seeds of this species and store them in the Iran's Natural Resources Gene Bank. Also, it should be planted in the National Botanical Garden of Iran so that, if necessary, it is possible to revive its population in nature.

To compare some ecomorphological, phenological and phytochemical properties of common mallow (Malva sylvestris L.) in two regions Ferdows and Tabas, three habitats from each region were randomly selected and studied in 2018. Soil analysis of the habitats indicated the growth of the plant in sandy loam soils. On the other hand, the soil of these two habitats was alkaline with low salinity. Soil lime content was higher than crop soils. The results of phenological studies also showed that in Ferdows, this plant grows in early April and blooms in June. Then the seeds begin to ripen in late October and fall in late November. In Tabas, the plant begins to grow in the second half of March, flowers in May and flowering continues until early autumn. The seeds start to ripen in the second half of August and fall in early November. In Ferdows and Tabas, the recession period of plant activities coincided with dryness of the environment and the onset of the cold season, respectively. Phytochemical analysis of leaves, flowers, seeds, and stems extracts of the plant in two regions showed the presence of alkaloids, tannins, flavonoids, emodol or emodine, saponins, carbohydrates, starch, sterols, steroids, anthocyanosides, and cumarins in low to high amounts in each organ of the plant. Anthracenoside was not found in any of the three ethanol, aqueous and ether extracts. Also, four phenolic acids (linoleic, linolenic, synergic, and paracomaric acids) were detected by thin-layer chromatography (TLC) in seeds, stems, flowers, and leaves of the plant in both areas. The results also showed that the anthocyanin content of the leaves decreased with increasing the region's altitude.

The temperature of water entering the soil or variation in soil temperature has a direct impact on soil hydraulic conductivity via the effect on water viscosity. In this research, the time variability of soil saturated hydraulic conductivity (Ks) was studied. The relation between soil temperature and fluid viscosity with hydraulic conductivity were also studied. The necessary experiments were conducted on Aboureyhan campus research farm located in Pakdasht, 25 km southeast of Tehran. 18 holes were digged in a plot and saturated hydraulic conductivity of soils were measured in these holes using inverse hole method. Experiments were carried out 12 times from 16-Aug-2005 to 14-Jun-2006. Investigations showed that the lowest value of Ks was obtained in winter when the soil and air temperatures are at minimum and by increasing the soil and air temperatures, these values increased too. Statistical analysis of experiments indicated that soil or air temperatures can considerably affect the results. Using the average of measured Ks to design drainage systems showed that neglecting the time variability of Ks may result in over or underestimating of drain spacing by 18.9% and 23.3%, respectively. Using the average of Ks values which was obtained in soil temperature of 16-20 oC had least effect on drain spacing, so it can be used as an average Ks to design drain spacing.

Background and objectives Water is the basis of life and health. The health of food and water supply plays an important role in human health. One of the methods of water desalination is membrane filter reverse osmosis method. This method is used for desalination of drinking water supply in Qom. Methods This is a deh1ive cross-sectional study designed to determine the quality of treated water in Qom desalination plant in year 2002. Inlet and outlet water samples of this plant were examined by the standard examination methods and the collected data were compared with national and international standards. Excel software was used for statistical analysis. Results The results showed that the residual chlorine concentration total hardness and fluoride concentration were lower than the minimum standard limit set for drinking water. The pH was also lower than the minimum standard limit. Microbial contamination was detected in 6% of samples. Conclusion The results show that the acidity of water was lower than standard in whole plant. This gives corrosive properties to the water and increases the dissolution of materials which are in contact with this water. In order to eliminate the secondary contamination the concentration of residual chlorine should be 1 mg/l. But none of the measurements showed a concentration as high as this value. As fluoride is an important element for health and growth of bone and teeth especially in growing children fluoride should be added to the drinking water. As the relationship between hardness of water and cardiovascular diseases has been established it can be concluded that this drinking water supply can increase the risk of cardiovascular diseases in long time. Dilution of this water is recommended to adjust various factors to the standard limits and keep the total dissolved solids low.