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排序方式: 共有347条查询结果,搜索用时 31 毫秒
71.
Bernd Schneider Manfred Stock Hartmut Bohm Gernot Schneider Horst-Robert Schütte Klaus Schreiber Angela Brauner Johannes Kster Ernst U. Kaußmann 《Pest management science》1994,41(4):327-333
Excised shoots from apple trees and cell suspension cultures were used as model systems to study the metabolism of [3,5-14C]amitrole in Malus domestica Borkh. Significant differences in the metabolism of the compound applied were observed with excised shoots, cultured cells and whole apple trees. The major metabolite in excised shoots was aminotriazolylalanine which occurred both in the free form and as conjugates. The major metabolite from whole plants. triazolylalanine, was detected in shoots in minor amounts only. In cell suspension cultures, the type of metabolism strongly depended on the concentration of amitrole when initially applied. At 10 ?3 m or lower, mainly aminotriazolylalanine was formed. Depending on the concentration of the active ingredient, this metabolite predominantly occurred in free form or as glycosides. At concentrations above 5 × 10?4 M a new metabolite, 3,5-dihydroxytriazole, was detected which was the only metabolite found at 5 × 10?3M. Significant amounts of nonmetabolized amitrole remained in the medium. 相似文献
72.
Gaede W Gehrmann B Körber R 《Berliner und Münchener tier?rztliche Wochenschrift》2003,116(5-6):234-239
With the long-term perspective of the eradication of BVD/MD in the German federal state Saxony-Anhalt a voluntary control program was initiated in 2002 by an administrative regulation based on federal German guidelines. The short-term aim of this program is the establishment of BVDV-unsuspected herds achieved by elimination of persistently infected cattle. The diagnostic program and particularly the choice of the diagnostic tools was based on the consideration of laboratory experiences as well as on economic and logistic aspects. A combination of RT-PCR and antigen-ELISA was found to be the suitable diagnostic methods. The screening started with examinations of sera pools using Real Time RT-PCR in the Light-Cylcer system. After positive pool results the individual persistently infected animals were detected using various commercial ERNS-antigen-ELISAs. The RT-PCR revealed a high degree of sensitivity and robustness. With respect to highly specific ELISAs the producers have to ensure the detection of all currently important virus strains. The prevalence of persistently infected animals in the cattle population of Saxony-Anhalt was about 0.2% during the last 3 years. This is probably due to nearly 10 years of broad vaccination and will prove advantageous for BVDV elimination. 相似文献
73.
Normal structure and age-related changes of the equine retina 总被引:2,自引:2,他引:0
Ehrenhofer MC Deeg CA Reese S Liebich HG Stangassinger M Kaspers B 《Veterinary ophthalmology》2002,5(1):39-47
Investigations of the pathophysiology of ocular diseases require a detailed knowledge of the microanatomy of the eye. The available information is still inadequate for the equine retina despite the importance of eye diseases in equine medicine. Here we provide a comprehensive analysis of the histologic features of the horse eye as a reference for future studies. Thirty normal eyes of 15 healthy horses were examined immediately after slaughter. The retina of the horse differs considerably in the degree and quantity of neurons and glial elements as well as in vascular patterns compared to the retina of other domestic animals. Morphometric analysis revealed that the thickness of the retina varies between 80 microm at the ora serrata and 250 microm medial to the optic disc. Approximately 90% of the equine retina is comparatively thin (< 130 microm). This is a physiologic response to the distance that oxygen can diffuse in avascular retina. Ganglion cells form a single layer in all parts of the retina. The majority of ganglion cells are very large Nissl-positive cells. Small Nissl-negative ganglion cells are less abundant. A high ganglion cell density is found only in the central area. Vascularization is virtually absent from the retina with the exception of a narrow strip around the disc of the optic nerve, as revealed by lectin histochemistry. Light microscopy of the eyes of older horses repeatedly revealed cystoid degenerations in the retina adjacent to the pars plana of the ciliary body, as well as a destruction of the regular layering of the peripheral region of the retina. 相似文献
74.
Christian Hoffmann Irena Savric Grzegorz Jozefaciuk Mieczyslaw Hajnos Zofia Sokoowska Manfred Renger Bernd Marschner 《植物养料与土壤学杂志》2002,165(1):67-71
Heavy metal polluted soils from a recent and a former sewage farm were studied in a 2.5 years‐column experiment under various irrigation regimes and/or liming treatment. The copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) concentrations in the soil and the leaching of these elements were studied. The amounts of the metals leached differed markedly between both soils, however, the effect of various irrigation treatments was less pronounced. The heavy metal content in the soil solid phase depended on the organic carbon content, however these dependencies differed for both soils as well as for particular metals. In lower soil horizons, the amount of heavy metals bound by unit mass of organic carbon was constant. It was assumed that the same amount of the heavy metals can be bound by the unit mass of the DOC. Under this assumption the amount of the DOC in the former sewage farm soil was in general too small to carry all heavy metals leached. Therefore leaching of their cationic forms has been postulated. The amount of the DOC in the present sewage farm soil could carry more heavy metals than these being leached. Therefore, an undersaturation of the DOC in heavy metals could occur in this soil.<?show $6#> 相似文献
75.
Samples of six Polish and three Korean soils were acidified and alkalized with elevated concentrations of hydrochloric acid or sodium hydroxide from 0.001 to 1 mol dm—3. The pore system of the studied soils was investigated using mercury intrusion (”︁macropores”) and water vapor adsorption (”︁mesopores”) experiments. The characteristics of the pores and their surfaces were very sensitive against acid and alkaline treatments. The macropore volume and radii increased in general with increasing of the concentrations of the treatment solutions. The macropore surface of all the clay rich soils exhibited a fractal behavior. The ranges of fractal scaling differed for particular soils. Macropore surface fractal dimensions changed under both treatments. For a given soil, the macropore fractal dimensions changed in the same direction under the effect of acid as under alkali. Both treatments decreased the mesopore volumes of Polish and increased the mesopore volumes of Korean soils. However, this was not true for two of Korean soils after extreme alkali treatments. In general, the average mesopore radius increased under lower treatments concentrations and decreased under higher concentrations. The mesopores were also fractal. The range of their fractal scaling was different for the Polish and Korean soils and roughly the same within each group. The fractal dimension of the mesopores decreased after acid treatment showing a smoothing of the material porous surface. Alkaline treatment affected the mesopore fractal dimension to a lower extent. A slight rise of the mesopore fractal dimension was noted in most cases.<?show $6#> 相似文献
76.
A map of soil texture profiles was derived from readily available spatial data in combination with information from soil profiles using CART (classification and regression trees). The primary purpose was to provide a regionalized predictor for the vertical hydraulic conductivity profiles to be used as an input variable to an evapo‐transpiration model. In contrast to former studies, the texture of 110 soil profiles taken in the 10 km2 area was not averaged vertically but the profiles were grouped according to their hydraulic properties. Therefore, it was possible to include site specific profiles, e.g. with histic or argillic horizons. Despite of small sampling quantities (110 soil profiles grouped into 8 classes) a prediction probability of 60 to 70 % was achieved in most classes. The resulting map provides valuable information for the granulometric and hydrologic characterization of the study area.<?show $6#> 相似文献
77.
78.
Thomas K. Gottschalk Tim Diekötter Klemens Ekschmitt Bernd Weinmann Friedrich Kuhlmann Tobias Purtauf Jens Dauber Volkmar Wolters 《Landscape Ecology》2007,22(5):643-656
Agricultural management is a major factor driving the change of faunal richness in anthropogenic landscapes. Thus, there is
an urgent need to develop tools that allow decision-makers to understand better intended and unintended effects of agricultural
policy measures on biodiversity. Here we demonstrate the potential of such a tool by combining a socio-economic model with
the biodiversity model GEPARD to forecast the response of bird and carabid species richness to two scenarios of agricultural
subsidies: (1) subsidies based on production levels and prices and (2) direct income support that is independent of production
levels. We focussed on farmland of the Lahn-Dill area, Germany, as an example of European regions with low intensity farming.
GEPARD predicts faunal richness and is based on multi-scaled resource-selection functions. Under both scenarios the area of
predicted losses in species richness of birds and carabids was larger than the area of predicted gains in species richness.
However, the area with predicted losses of avian richness was smaller under the direct income support scenario than under
the production-based subsidy scenario, whereas the area with predicted losses of carabid species richness was smaller under
the production-based subsidy scenario than under the direct income support. Yet locally, richness gains of up to four species
were predicted for carabids under both scenarios. We conclude that the sometimes contrasting and heterogeneous responses of
birds and carabids at different localities suggest the need for spatially targeted subsidy schemes. With the help of the GIS-based
approach presented in this study, prediction maps on potential changes in local and regional species richness can be easily
generated. 相似文献
79.
Wheat-barley translocations were identified by genomicin situ hybridization (GISH) in backcross progenies originating from in vitro regenerated wheat (Triticum aestivum L. cv. Chinese Spring) × barley (Hordeum vulgare L. cv. Betzes) hybrids. The regenerated hybrids were pollinated with the wheat line Martonvásári 9 kr1. Five translocated
wheat-barley chromosomes were recovered among 51 BC2F2 progeny from the in vitro regenerated wheat × barley hybrids. All were single breakpoint translocations with the relative positions of the breakpoints
ranging from the centromere to about 0.8 of the relative arm length. Of the four translocations with intercalary breakpoints,
three were transfers of terminal barley segments to wheat chromosomes; one was a transfer of a terminal wheat segment to a
barley chromosome. Because of the absence of diagnostic N-bands, the identity of three barley segments could not be determined;
in one translocation the barley chromosome involved had a NOR so it must have been 5H or 6H, and the centric translocation
was 4HS.2BL. Following selfing, homozygotes of four translocations were selected. The experiment suggests that in vitro culture conditions are conducive for major genome rearrangements in wheat-barley hybrids.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
80.
Tropical forests contain many tree species that have supplied edible fruits for centuries.These fruits have contributed to human diets due to their richness in nutrients,vitamins,minerals,antioxidants and their low antinutrients content.We investigated the antioxidant,nutritional and anti-nutritional composition of Garcinia kola and Chrysophyllum albidum fruit parts.The nutritional,anti-nutritional and antioxidant compositions differed depending on the fruit part.Irrespective of fruit part,moisture content was high(72–93 %).While the edible part(fruit pulp) of C.albidum proved a better source of protein(4),fibre(17 %) and fat(2 %),the seed kernel was a better source of ash(2 %) and carbohydrate(15 %).Carbohydrate(22 %),protein(2 %),fat(1 %) and fibre(3 %) were higher in G.kola seed kernel(edible part) than in the pulp and pod.Anti-nutrient content in G.kola and C.albidum fruits was low,indicating that their consumption would not pose nutritional or health problems.The antioxidant compositions(especially phenolic content(10–21 mg g-1) and DPPH(1,1-diphenyl–2 picrylhydrazyl)(26–55 %)) of C.albidum fruit pulp and G.kola seed kernel were high,implying that they could be good sources of natural antioxidants and could be used as supplements in food manufacturing. 相似文献