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51.
Water flow and solute transport in furrow-irrigated fields 总被引：3，自引：0，他引：3
Fariborz?AbbasiEmail author Jan?Feyen Robert?L.?Roth Mike?Sheedy M.?T.?van?Genuchten 《Irrigation Science》2003,22(2):57-65
Field-scale solute transport experiments are not easily implemented because of the overwhelming problems of soil heterogeneity and variability in subsurface hydraulic and solute transport properties. In this paper, the results of four field-scale furrow irrigation experiments designed to investigate the effect of flow depth and solute application time on bromide distribution along and below the furrows are presented. One experiment was conducted under free-draining (FD) conditions in which bromide was applied during the entire irrigation event. Three experiments were carried out in blocked-end furrows in which bromide was injected either during the entire irrigation event (100%), the first half of the irrigation (FH), or the second half of the irrigation (SH). The FD experiment was equipped with neutron probe tubes for measuring soil water contents at different times and locations in furrow cross-section whereas soil samples for bromide analysis and gravimetric soil water contents from all the experiments were collected at different depths up to 1.80 m, 5 days after the irrigation at three locations near the inlet, in the middle, and close to the outlet of the furrows. Overland flow depths along the furrows were also recorded using staff gauges at the inlet, middle, and outlet sites every few minutes during the entire irrigation. Results showed substantial non-uniformity in solute movement along the monitored furrows, with the degree of non-uniformity depending upon flow depth and solute application time. Non-uniform distributions were observed especially at the outlet sites, compared with those at the inlet and middle sites. Solute application efficiencies for the FD, 100%, FH, and SH experiments were 50, 100, 64, and 93%, respectively. The effects of flow depth and irrigation/solute application time on soil water contents were more pronounced in the soil surface layers and were found to be relatively minor at deeper depths. Water and solute deep percolation rates also showed dependency to flow depth and solute application/opportunity time and gradually decreased along the furrows. 相似文献
52.
Effects of high-pressure treatment (HPT) on the rheological parameters and gelation of iota-carrageenan (iota-Car) and mixtures of micellar casein (MC) and iota-Car have been investigated under neutral pH conditions. It was established that HPT showed no significant effect, in the presence or absence of ionic calcium, with or without initial thermal processing, on the rheology or gelation/melting temperatures of the pure iota-Car solution. However, in mixed systems containing varying concentrations of iota-Car (up to 1 wt %) and MC (up to 8 wt %), considerable changes were detected. At the higher molar ratios of MC to iota-Car, and especially at the higher pressures, the dispersions were not thermoreversible in gelation, presumably due to the strong interactions of disrupted casein micelles with iota-Car molecules, as well as due to the formation of a dominant proteinaceous network at higher concentrations of MC. The associative protein-polysaccharide interactions in these systems are highly dependent on the ionic calcium content. 相似文献
53.
The influence of high-pressure treatment (HPT) (200-800 MPa, 5 or 20 min, at 20 degrees C) on the rheological properties of solutions of amidated low-methoxyl pectin (LMP) and its mixtures with micellar casein (MC) has been investigated in the presence and absence of sucrose. The storage modulus G' of LMP gels containing 0-55 wt % sucrose and 0.1-1 wt % LMP was found to increase significantly following HPT at >or=400 MPa. Various concentrations of LMP in the presence of different amounts of MC (0.5-12 wt %) showed contrasting types of rheological behavior. In the presence of a low concentration of LMP (<0.3 wt %), HPT was found to induce a sol-gel transformation at relatively high LMP/MC molar ratios (<4 wt % MC), to reduce values of G' and the loss modulus G' ' at intermediate LMP/MC ratios (4-10 wt % MC), and to increase the values of G' and G' ' at low LMP/MC ratios (>10 wt % MC). In contrast, in the presence of a higher amount of LMP (>0.5 wt %), it was observed that HPT enhances the values of both the storage and the loss moduli over the whole range of MC concentrations. 相似文献
54.
Histophilus somni is an important pathogen of cattle and sheep. H. somni requires iron and can use ruminant transferrins as iron sources for growth. Here, we investigated the abilities of bovine (strains 649 and 2,336) and ovine (strains 9L and 3384Y) isolates of H. somni to acquire iron from haemoglobins. Using growth assays, the bovine isolates were shown to acquire iron from bovine haemoglobin, but not from ovine, porcine or human haemoglobins; the ovine isolates, however, failed to use any of these haemoglobins as iron sources for growth. In solid phase binding assays, the bovine isolates, grown under iron-restricted conditions in the presence of bovine haemoglobin, bound not only bovine but also ovine and human haemoglobins. Competition binding assays indicated that all three haemoglobins were bound by the same receptor(s) and SDS-PAGE of membrane fractions revealed that expression of haemoglobin-binding activity was associated with the production of an approximately 120-kDa outer membrane protein. PCR approaches allowed the amplification and sequencing of hgbA, and also hugX and hugZ homologues from strains 649, 9L and 3384Y. While hgbA of strain 649 was predicted to encode an HgbA precursor that is processed to yield a mature, 123.9-kDa haemoglobin-binding protein, the hgbA genes of strains 9L and 3384Y were predicted to give rise to truncated products. RT-PCR experiments revealed that in strain 649, hugX, hugZ and hgbA are co-transcribed and iron-regulated and additional sequencing suggested that in strain 2336, expression of HgbA is subject to phase variation involving a poly C tract within hgbA. 相似文献
55.
Liu CZ Abbasi BH Gao M Murch SJ Saxena PK 《Journal of agricultural and food chemistry》2006,54(22):8456-8460
Inoculation of leaf explants of Echinacea purpurea (Moench) with Agrobacterium rhizogenes induced hairy roots with the capacity to produce biologically active caffeic acid derivatives (CADs), especially cichoric acid. The kinetics of growth, the uptake of macronutrients, and the accumulation of CADs were investigated in heterotrophically cultured hairy roots for a 50 day period. A maximum of 12.2 g L(-1) dry biomass was achieved in MS nutrients supplemented with 30 g L(-1) sucrose on day 40. The mathematical relationship between hairy root growth and conductivity was established during the exponential phase in Erlenmeyer flasks. HPLC analyses of methanolic (0.1% phosphoric acid; 70:30, v/v) extracts from hairy roots revealed the presence of important CADs: cichoric acid (19.21 mg g(-1) dry biomass), caftaric acid (3.56 mg g(-1) dry biomass), and chlorogenic acid (0.93 mg g(-1) dry biomass). These results demonstrate that biotechnological production of CADs in hairy roots of E. purpurea is possible. Furthermore, these hairy root cultures offer, for the very first time, an excellent biological model to study the biosynthetic pathway of medicinally important CADs. 相似文献
56.
Yoshihiro Matsuoka Mohammad Jaffar Aghaei Mohammad Reza Abbasi Abdolhosain Totiaei Javad Mozafari Shoji Ohta 《Genetic Resources and Crop Evolution》2008,55(6):861-868
Hexaploid bread wheat (Triticum aestivum L. ssp. aestivum) is assumed to have originated by natural hybridization between cultivated tetraploid Triticum turgidum L. and wild diploid Aegilops tauschii Coss. This scenario is broadly accepted, but very little is known about the ecological aspects of bread wheat evolution.
In this study, we examined whether T. turgidum cultivation still is associated with weedy Ae. tauschii in today’s Middle Eastern agroecosystems. We surveyed current distributions of T. turgidum and Ae. tauschii in northern Iran and searched for sites where these two species coexist. Ae. tauschii occurred widely in the study area, whereas cultivated T. turgidum had a narrow distribution range. Traditional durum wheat (T. turgidum ssp. durum (Desf.) Husn.) cultivation associated with weedy Ae. tauschii was observed in the Alamut and Deylaman-Barrehsar districts of the central Alborz Mountain region. The results of our field
survey showed that the T. turgidum–Ae. tauschii association hypothesized in the theory of bread wheat evolution still exists in the area where bread wheat probably evolved. 相似文献
57.
Muhammad Sufyan Asim Abbasi M. Dildar Gogi M. Arshad Ahmad Nawaz Daniel Neuhoff 《Gesunde Pflanzen》2017,69(4):197-202
Wireworms, the larvae of click beetle species Agriotes lineatus, A. obscurus and A. sputator are serious pests for several field crops. They are considered severe pests of potato tubers and the damages caused by them can be resulted a significant loss especially in organic crop production. Since synthetic insecticides are prohibited in Organic Farming; biological control methods have to be used in organic crop production. In the current study naturalis Beauveria bassianaa strain ATCC 74040 was used both under laboratory and field conditions using wheat and potato crops as a food source respectively. Fungus showed a significant mortality in high number of wireworms boxes (50%) compared to low number of wireworms (17%) and untreated boxes (13%) respectively. However, seed germination showed no effect in all three categories. Field data have shown mixed results when B. bassiana has been applied in a variety of application methods. Maximum infestation (3.99%) was recorded in untreated plots; while significantly lower damage (1.11%) was recorded in whole surface treated plots. During first year all the treatments were significantly different from each other; however, no significant differences were noted between furrows and whole surface applications but were different from control treatment during second year of experimentation. The results showed that the biological control of wireworms by using entomopathogenic fungi, such as B. bassiana is a promising target specific option without disturbing the other communities in the soil. 相似文献
58.
Shahryar Abbasi Mahmoud Roushani Yar Mohammad Baghelani Sayed Zia Mohammadi Maryamosadat Mavaei 《Communications in Soil Science and Plant Analysis》2017,48(16):1921-1930
In this study, a new Co3O4 nanoparticles (NPs) coated with sodium dodecyl sulphate (SDS) is developed for preconcentration of trace amounts of cadmium ions (Cd 2+) as a prior step to its determination by flame atomic absorption spectrometry (FAAS). The effects of various parameters, including pH of sample solution, amount of sorbent, flow rates of solution and eluent, sample volume, type, and least amount of the eluent for elution of the Cd 2+ from Co3O4 NPs were studied and optimized. Experimental conditions for effective separation of trace levels of the Cd 2+were optimized with respect to different experimental parameters in Column method. Under the best experimental conditions, the calibration curve was linear in the range of 1.0–500.0 ng.mL?1 of cadmium (Cd) with R2 = 0.999. The detection limit was 0.4ng.mL?1 in the original solution (3Sb/m) and the relative standard deviation for eight replicate determination of 0.1µg.mL?1 Cd was ±2.1%. The method was validated by the analysis of a certified reference material with the results being in agreement with those quoted by manufactures. The developed method was successfully applied to the extraction and determination of Cd in water and food samples with satisfactory results. 相似文献
59.
Hosseininia M. Hassanpour F. Naghavi H. Abbasi F. Bastani Sh. 《Eurasian Soil Science》2019,52(10):1214-1222
Eurasian Soil Science - Soil salinity is a major problem in Kerman pistachio (Pistacia vera) orchards which caused low pistachio’s productivity in recent years. Farmers excessively use gypsum... 相似文献
60.
This paper describes the embryonic development of the common cutworm Spodoptera litura （Fabricius） （Lepidoptera： Noctuidae） which is divided into eight embryonic stages, through variations in the egg＇s contents. Experiments were conducted on the eggs ofS. litura under laboratory conditions. The highest concentration of the protein （min.-max.： 32-! 40 lag/egg） and the lowest of the carbohydrate （min.-max.： 3.0-44.0 lag/egg） were obtained; similarly, the DNA content was smaller （min.-max.： 1.0-38.2 lag/egg） than the RNA （min.-max.： 9.2-360.0 lag/egg） throughout the embryogenesis. Three peaks of ecdysteroid titre were observed which were responsible for appearance of particular events during embryogenesis. The last highest peak of 400_＋33.4 lag/egg was appeared at 84 h after oviposition when larva was ready to hatch. Therefore, it is concluded that eight embryonic stages in S. litura were characterized by fluctuation in the egg＇s contents, which were responsible for gradual-progressive embryonic development. The egg-larval development did not show a normal distribution of embryonic developmental-time. 相似文献