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Phenanthrene sorption by compost humic acids 总被引：4，自引：0，他引：4
Nonlinear isotherms were observed for sorption of polycyclic aromatic hydrocarbons (PAHs) to humic materials, but the exact sorption mechanism is not clearly understood. This study aimed to investigate the sorption of PAHs by compost humic materials. Humic acids (HAs) were progressively extracted from two compost samples by a 0.1-M sodium pyrophosphate solution. Sorption of phenanthrene by the extracted HAs was studied with a batch equilibration technique. Competitive sorption between pyrene and phenanthrene in the HAs was also examined. Elemental analysis and solid-state 13C NMR were used to characterize HAs. All sorption isotherms were nonlinear although these samples contained little black carbons if any. Isotherm linearity increased with increasing number of extractions. Isotherm nonlinearity was negatively related to HA aliphaticity. Addition of pyrene to the phenanthrene-HA system increased isotherm linearity. Competition between phenanthrene and pyrene sorption was more pronounced in the first fraction of HAs with a higher content of aromatic moieties. This study showed that humic materials alone could lead to nonideal sorption for PAHs. 相似文献
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Hossein Tabari Safar MarofiAli Aeini Parisa Hosseinzadeh TalaeeKurosh Mohammadi 《Agricultural and Forest Meteorology》2011,151(2):128-136
Reference evapotranspiration (ETo) is an important element of the hydrological cycle, and changes in ETo are of great significance for agricultural water use planning, irrigation system design and management. In this study, annual, seasonal and monthly trends in the Penman-Monteith ETo at 20 meteorological stations during 1966-2005 in the western half of Iran were examined using the Mann-Kendall test, the Sen's slope estimator and the linear regression. Annual analysis of the ETo series indicated a positive trend in 70% of the stations according to the Mann-Kendall test and the Sen's slope estimator and in 75% of the stations according to the linear regression. The magnitude of significant positive trends in annual ETo varied from (+)11.28 to (+)2.30 mm/year. On the seasonal scale, stronger increasing trends were identified in ETo data in winter and summer compared with those in autumn and spring. Meanwhile, the highest numbers of stations with significant trends were found in the monthly ETo series in February, while the lowest numbers of stations with significant trends were observed in November. Analysis of the impact of climatic variables on the significant increasing trend in ETo showed that the increasing trend was mainly caused by a significant increase in air temperature during the study period. 相似文献
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Parisa Delfieh Hedayat Hosseini Seyed Vali Hosseini Ehsan Zohrehbakhsh Joe M. Regenstein 《Journal Of Aquatic Food Product Technology》2013,22(4):353-360
The effects of baking, boiling, microwaving, and frying on the proximate composition and fatty acid content of the edible portion of Indian white prawns (Fenneropenaeus indicus) were determined. Mean moisture, lipid, protein, and ash contents of raw prawns were 72.1, 4.32, 21.5, and 1.31%, respectively. For all cooking methods, moisture decreased and protein increased, while fatty acid compositions changed uniquely for each method. In fried prawns, the n3/n6 ratio was the lowest and significantly differed from the other treatments. The heat treatment significantly changed the proximate composition and fatty acid content. Baking and microwaving are the best methods of the four for cooking prawn while preserving their nutritional value, especially on the basis of recommended dietary intake of DHA and EPA. 相似文献
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Tapan Adhikari Dipayan Sarkar Hamid Mashayekhi Baoshan Xing 《Journal of plant nutrition》2016,39(1):99-115
Copper (Cu) is an essential micronutrient for plants, which acts either as the metal component of enzymes or as a functional structural or a regulatory co-factor of a large number of enzymes. To understand the possible benefits of applying nanotechnology to agriculture, the first step should be to analyze penetration and transport of nano-particles in plants. The present study was conducted to test the hypothesis that copper nanoparticle would enter into the plant cell and govern the growth of maize plant.A solution culture experiment was conducted to investigate the effect of Cu nano-particles (<50nm) on the growth and enzymatic activity of maize (Zea mays L.) plant. Bioaccumulation of Cu nano-particles in plant was also investigated. Results showed that Cu nano-particles can enter into the plant cell through roots and leaves. Bioaccumulation increased with increasing concentration of Cu nano-particles (NPs), and agglomeration of particles was observed in the cells using transmission-electron microscopy. Application of Cu nano-particles through solution culture as well as spray enhanced the growth (51%) of maize plant in comparison to control. The different enzymatic activities like glucose-6-phosphate dehydrogenase, succinate dehydrogenase, superoxide dismutase, catalase, andguaiacol peroxidase were studied to find a possible pathway through which NPs may affect the enzymatic activity of plant. Amongst the enzymes, the activity of glucose-6-phosphate dehydrogenase was highly influenced by copper oxide (CuO)nano-particles application by spray as well as in solution. Experimental results revealed that CuOnano-particles affected the pentose phosphate pathway of maize plant. The obtained experimental results provided conclusive evidence to indicate that the nano-particles considered under this study could enter into the plant cell, easily be assimilated by plants and also enhanced its growth by regulating the different enzyme activities. 相似文献
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Ahmad Bybordi Saaed Saadat Parisa Zargaripour 《Archives of Agronomy and Soil Science》2018,64(4):520-530
Considering the importance of onion and its cultivation in saline soils, a two-year experiment was carried out to investigate the effects of soil applied zeolite and foliar application of selenium (Se) and silicon (Si) on onion yield, qualitative traits and physiological attributes, under salinity stress. An experiment was performed at three-way factorial design with three replications as follows: zeolite at three levels (0, 4 and 8 ton ha-1), Se at three levels (0, 0.5 and 1 kg ha-1) and Si at three levels (0, 200 and 400 kg ha-1). The results indicated that the effect of year was significant on all studied traits except for soluble solids, bulb nitrogen, leaf sodium and potassium, chlorophyll content and peroxidase activity. Number of small-sized bulbs decreased with increasing zeolite, Se and Si application. Dry matter, soluble solids, nitrogen content, nitrate concentration as well as protein content significantly increased due to zeolite, Se and Si application. Leaf sodium content and enzyme activity decreased due to zeolite, Se and Si application. Overall, 8 ton ha-1 zeolite along with 1 kg ha-1 Se and 400 kg ha-1 Si caused the maximum onion yield and qualitative and physiologic traits including soluble solids, potassium, protein, chlorophyll and photosynthesis . 相似文献
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Pathogenic microorganisms are commonly associated with external ocular infections in birds. Pathogen virulence factors as well as reduced host defenses resulting from poor living conditions, nutrition, genetics, physiology, hygiene, fever, and age may increase host susceptibility. Staphylococcus species are bacteria known to serve as opportunistic pathogens in eye infections. The changing profile of microorganisms involved in ocular infections and the emergence of acquired microbial resistance dictate the need for investigative studies regarding bacterial profiles and antimicrobial susceptibility patterns for external ocular infections. The aim of this study was to determine the prevalence of Staphylococcus aureus ocular infections in pigeons and to evaluate their biofilm production ability and antibiotic resistance patterns. Twenty pigeons with confirmed eye infections were included in this project. Conjunctival specimens were collected with swabs presoaked in sterile normal saline. Bacterial growth was identified by standard laboratory procedures and susceptibility testing of the isolates was performed by the Kirby-Bauer method. The ability of the isolates to form a biofilm was also assessed using the microtiter plate method. Of the 20 specimens processed, 20% of the pigeons had staphylococcal eye infections. The resistance pattern of these isolates showed that Staphylococcus spp. from pigeon samples were resistant to tetracycline (100%), erythromycin (100%), azithromycin (100%), nalidixic acid (100%), and cefazolin (50%). All of the Staphylococcus spp. isolated from the pigeons were susceptible to gentamycin and furazolidone. The results of the biofilm detection test showed that 75% of the isolates were biofilm producers. In conclusion, biofilm forming S. aureus with multidrug resistance patterns were the most prevalent bacteria isolated from the pigeons examined in this research study. 相似文献
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The present experiment was conducted to assess the role of silicon (Si; 0, 100, 200, and 300?mg L?1 Na2SiO3) in mitigating heat stress-induced growth deficiency, photosynthesis inhibition, and oxidative damage in soybean cultivars. Heat stress lowered root and shoot dry weights, which were noticeably improved by Si supplementation. Exposition to 200?mg L?1 Si caused a 45 and 34% increase in chlorophyll and Fv/Fm, respectively, compared to plants that received no Si. Net photosynthetic rate, intercellular CO2, and stomatal conductance were lowered due to heat stress and Si supplementation mitigated the adverse effect of heat stress on these attributes. Furthermore, lipid peroxidation, hydrogen peroxide generation, and electrolyte leakage were higher in heat-stressed soybean cultivars without Si as compared to those supplemented with Si. Accumulation of osmolytic cytosolutes such as proline and glycine betaine was also boosted by Si supplementation. In addition, Si treatment alleviated the destructive effects of heat stress by 63, 64, and 50% increases in total phenol, flavonol, and tocopherol contents, respectively. Interestingly, including Si in the heat-stressed soybean cultivars improved protein content and enhanced the activities of catalase, phenylalanine ammonia lyase, and lipoxygenase, while the activities of superoxide dismutase, peroxidase, and polyphenol oxidase were lowered by 30, 56, and 54%, respectively, compared to non-Si-treated cultivars. In conclusion, Si alleviated the adverse effect of heat stress in soybean cultivars by modulating photosynthesis, further accumulating osmolytes, and regulating the antioxidant system. However, large-scale and long-term field trials must be carried out to investigate the economic feasibility of Si application for alleviating heat shock stress.
相似文献29.
Nik M. Majid M.M. Islam Redzuan Abdul Rauf Parisa Ahmadpour Arifin Abdu 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):245-250
Abstract Heavy metal pollution is a widespread global problem causing serious environmental concern. Cadmium, one of the heavy metals, is water soluble and can be transferred from soil to plants and enter into the food chain. It is detrimental to human health because it accumulates in the body and can cause renal tubular dysfunction, pulmonary emphysema and osteoporosis. This heavy metal needs to be cleaned up for a clean and safe environment. An experiment was conducted to evaluate the potential of Dyera costulata as a phytoremediator to absorb cadmium from contaminated soils. Dyera costulata seedlings were planted on six different growth media (soil + different levels of cadmium): Control, 25 ppm Cd, 50 ppm Cd, 75 ppm Cd, 100 ppm Cd and 150 ppm Cd. The highest growth performance mainly height, basal diameter and number of leaves were in the control, 50 ppm Cd and 25 ppm Cd treatments, respectively. The highest accumulation of cadmium (52.9 ppm) was in the 75 ppm Cd treatment. Among the plant parts, leaves showed the highest concentration of cadmium. Dyera costulata showed high translocation factor and low bioconcentration factor values in soil at high cadmium concentrations and was also able to tolerate and accumulate high concentrations of cadmium. The roots of Dyera costulata were found to be suitable for the absorption of cadmium in contaminated soils. This species can be an efficient phytoremediator for soils contaminated with cadmium. 相似文献
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