جستجوی مقالات مرتبط با کلیدواژه « زنده مانی » در نشریات گروه « محیط زیست »

Electromagnetic fields and radio frequency radiation interact in human body tissues and can have effects on reproduction and the most mentioned side effects of the impact waves is in the enzyme reproductive system, male sex hormones, bone marrow, heart rate, hematological changes and neurobehavioral disorders.. This research is to investigate different electromagnetic intensity on some parameters of ram semen and TBARS stress index as an animal model. After semen collection with the help of an artificial vagina, samples were placed in a device that produces electromagnetic waves with different intensities, including control, 1, 1.5, 2, 2.5, 3, and 3.5 millitesla (mT). The Semen parameters were evaluated with a microscope equipped with a computer, Computer Assisted Sperm Analysis (CASA). The sperm viability was determined by Dif Quick kit. The highest motility was at the intensity of 1 mT and the lowest at 2 mT (85% vs 45.5%). The sperm motility increased at 3 mT and reached 74%, but then decreased significantly at 3.5 mT intensity and reached 50.5%. The Sperm viability in 3 and 3.5 mT reached 76.4 and 85.2% respectively. There was a significant decrease in viability at the intensity of 2.5 mT compared to other treatments. The concentration of TBARS significantly decreased at the intensity of 3 mT compared to the control group and other treatments. The dissimilar intensities create different effects. It is possible to get help some intensity in sterility treatment.

This study was carried out to investigate the effect of Microcystin-RR (MC-RR) extracted from Microcystis aeroginosa microalgae on Daphnia magna and determine the lethal concentration of this toxin (LC50-96h). Twenty-one Daphnia magna were exposed to concentrations of 0.5, 2, 10, 20 and 50 μg.ml-1 of MC-RR Microcystin in each replicate, and the daphnia survival for 24 to 96 hours was calculated. One treatment was considered as control (no toxin), each treatment had 3 replications. According to the results of this study, microcystin (MC-RR) had a lethal effect on Daphnia magna, so that even at a low concentration (concentration of 0.5), about 38% of mortality was observed, and none of the Daphnia magna had the ability to survive at 2 μg.ml-1 of pure MC-RR Microcystin for 96 hours. This ability decreased by increasing the concentration of poison, so that at the concentration of 10 μg.ml-1 of Microcystin, on the second day and at concentrations of 20 and 50 μg.ml-1 of poison, all daphnia were dead on the first day. The results of this study showed that in the concentration of 1.75 μg.ml-1 MC-RR Microcystin, during 96 hours, 99 percent of daphnia were died.

The aim of this study was to assess the adaptability and performance of Eucalyptus species under dry weather conditions of Semnan city along with irrigation. Therefore, an experiment was conducted in 2008 in the suburb of Semnan in a randomized complete block design with three replications and nineteen treatments with a planting distance of 4*4 meters.Twenty-four seedlings were planted in each replicate and continued till 2013. Treatments included Eucalyptus species and provenances including E. camaldulensis, E. campaspe, E. largiflorens, E microtheca Fars, E. rubida sh-166, E. saligna sh-168, E. viminalis sh-168, and so on. The inventory consisted of three traits: viability percentage, total height, and collar diameter. Data were analyzed using analysis of variance (ANOVA) and Duncan test in the SPSS software.The results showed that the resistance of the species studied was different in this region, so that the species E.viminalis sh-168 was completely destroyed and the E. campaspe showed very little adaptation. The E. rubida sh-166 and E. saligna sh-168 showed low resistance. The most successful Eucalyptus species were E. camaldulensis Zh-41, E. camaldulensis 9616, E.camaldulensis Ch- 41and E. camaldulensis Sh- 41. In this research, the best provenances from the tested treatments that have been able to obtain a mean height of 10 to 11 meters within five 5 years are introduced.

Mediterranean Cypress (Cupressus sempervirens var. fastigiata) is a native, evergreen species. Due to its various merits, particularly its wide use in parks and urban green spaces, it is of interest in most climatic regions of Iran, including Zagros provinces. Due to the poverty of soil and limitation in water sources, the production of seedlings of this species has become particularly problematic in some of these regions. By using rhizobacteria Pseudomonas fluorescens inoculation in soil, for the first time, the present study aims to determine the resistance and variations of growth characteristics of seedlings under water deficit conditions. The experiment was conducted as a factorial, using a completely randomized design with two treatments (i.e., with rhizobacteria and without rhizobacteria), different watering levels (3, 6, 9 and 12 days) in three replicates. After 5 months, growth characteristics of seedlings were measured. Increasing the watering period (water deficit) caused to significantly decrease the survival, diameter, shoot biomass and total biomass, so that all seedlings were died under 12-day watering level. In watering period of 9 days, survival was reduced to 49.83 percent. There was no significant difference in collar diameter, root length, root volume and root/shoot biomass with water deficit intensity. However, the survival rate, height growth, shoot biomass, root biomass, total biomass and seedling quality index were greater in seedlings inoculated with rhizobacteria, compared with those of non-inoculated seedlings. The seedlings of Mediterranean Cypress inoculated with Pseudomonas fluorescens rhizobacteria are able to tolerate the water deficit stress and increase their growth performance; however, under optimal conditions, the rhizobacteria inoculation has no positive effect on survival rate of the seedlings.

Judas tree belongs to valuable species in Zagros forests. Nowadays, due to the special beauty of this species, it has received substantial attention in afforestation. In this regard, the improvement of seed germination is a suitable way to improve the quantity and quality of producing seedlings in nurseries and the establishment of forest plantation. In this study, the seed germination characteristics and seedling survival of Cercis griffithii in different soil treatments have been surveyed in the nursery of Aivan County in Ilam province. The experiment was set up as a randomized complete design with four treatments each contained 120 pots. Three seeds in plastic pots were sown in nursery soil (Control Control soil- cattle manure (5:1), Control soil- Litter (5:1) and Control soil- Cattle manure- Litter (5:1:1). According to the one-way ANOVA results, significant differences were observed between soil treatments in terms of germination rate, maximum, mean daily germination and germination energy, while there were no significant differences in other germination characteristics between soil treatments. The highest germination rate, maximum, mean daily germination and germination energy were observed in the treatment of Control soil- Cattle manure- Litter. In terms of time, seedling survival decreased from September to March. The results showed that there is a significant correlation between mean daily germination and different soil composition. In general, it can be concluded that germination and survival of Cercis griffithii can be improved using organic compounds in the nursery.

Assessment of the plantation is fundamental for managers to improve plantation quality and successful plantation in the future. This study aimed to assess and compares Makhmalkooh forest park plantation data due to 18 years old period. Sampling was performed in a randomized systematic design using 60 circular plots in a 50*150 m rectangular grid. Diameter at breast height, basal area, tree height and crown canopy were measured for each species in all plots, and then total volume and mean of growth increment based on age were computed. Results showed that Cupressus arizonica and Amygdalus scoparia had the highest value in density, heterogeneity in species composition, and crown canopy and Capressus sempervirens and Olea europea had the least one. The survival rate for all species were 78.5 percent and different plantation types showed significant difference in diameter, basal area, crown canopy and total volume. The most value in mean of diameter and height increment was assigned to Pinus brutia and Cupressus sempervirens and the least value were assigned to Olea europea and Amygdalus scoparia. The results showed that Cupressus arizonica and Pinus brutia are the best species for afforestation in this region.