نتایج جستجو برای: species composition
تعداد نتایج: 776958 فیلتر نتایج به سال:
Plant litter is an important factor for soil conservation and sustainability that could modify soil chemical properties and increase the plant biomass production. The aim of this research was to compare plant litter chemical composition and its effects on soil properties in three species including Hordeum bulbosum, Poa bulbosa, Bromus tectorum. First, soil samples were taken in the depth of 0-3...
Previous studies have demonstrated that there is a change in the molecular species specificity of CMP-N-acetylneuraminate:lactosylceramide alpha 2,3-sialyltransferase (LacCer alpha 2,3-ST) when the lipid composition of the Golgi membrane is altered (Kadowaki, Grant, and Williams, 1993. J. Lipid Res. 34: 905-914). To understand the basis of this phenomenon, the molecular species specificity of r...
Asian seabass (Lates calcarifer) is a potential candidate species for rearing in pond system in Iran because of its fast growth rate, ability to adapt to varying environmental conditions and its demand in domestic as well as export markets. Hence, growth parameters, survival and body composition of Asian seabass (20.70±0.36 g) was investigated. Experiment was conducted in three ponds In Choebde...
The origin of a new diploid species by means of hybridization requires the successful merger of differentiated parental species' genomes. To study this process, the genomic composition of three experimentally synthesized hybrid lineages was compared with that of an ancient hybrid species. The genomic composition of the synthesized and ancient hybrids was concordant (rs = 0.68, P < 0.0001), indi...
Methods Data on species composition for both taxonomic groups were collecting using standard inventory methods for birds and butterflies in temperate regions. Data were compiled at three sampling grains, sites (average 12 ha), canyons (average 74 ha) and mountain ranges. For each sampling grain in turn, we calculated similarity of species composition using the Jaccard index. First, we investiga...
Relationships between species composition and its environmental determinants are a basic objective of ecology. Such relationships are scale dependent, and predictors of species composition typically include variables such as climate, topographic, historical legacies, land uses, human population levels, and random processes. Our objective was to quantify the effect of environmental determinants ...
The aim of the present study was to isolate cyanobacteria from oil refinery waste water and detection of antagonistic activity of their extracts on four species of pathogenic bacteria. The cyanobacterium was isolated and purified on Blue green algae medium number 11 (BG-11) medium. Methanol and water extracts prepared from the cultured cyanobacterium after 45 days growth on BG-11 medium. The bi...
In many studies, topographic factors have been considered as an important factor in establishing the vegetation in different ecosystems. So, it affects vegetation composition and diversity by influencing soil moisture, fertility and soil depth. The aim of this research was to investigate the effects of slope, elevation and geographical aspects on species growth, forage production and vegetation...
Short-term changes (5 years) in canopy cover, species composition and forage production were studied under protection from grazing and grazed condition in 19 range sites in Fereydan region, Isfahan province. In this study, density, canopy cover and forage production data were obtained from quadrates inside and outside exclosures in the spring of 1983. These parameters were studied again in 1988...
Considering the importance of plant diversity and to evaluate the effect of grazing pressure on species richness and structure of plant communities, this experiment was conducted at Golestan National Park and its surrounding areas in the north east of Iran. Sampling was conducted in intact and abandoned habitats and habitats under seasonal and heavy grazing, using Modified Whitaker Plot in 1, 1...
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