The influence of the radiation environment around the node on morphogenesis and growth of white clover (Trifolium repens)   总被引：4，自引：0，他引：4  

L. THOMPSON 《Grass and Forage Science》1993,48(3):271-278

The growth of clonally propagated clover plants ( Trifolium repens ) in the glasshouse was compared with their growth under canopies of Tropaeolum peregonium with or without supplementation from red light emitting diodes (LEDs) directed at the youngest node bearing a fully expanded leaf. The T. peregonium was grown over a net support so that its roots did not meet those of the clover. A similar experiment was set up in a permanent grassland using canopy shade from various grass species ( Holcus lanatus, Lolium perenne and Agrostis stolonifera ) with and without supplementation. The LEDs increased the ratio of red to far red radiation (R/FR) received by the treated node with no apparent increase in photosynthetically active radiation (PAR) during the day.
The morphogenetic effects of canopy shading (notably fewer branched nodes and less well-developed branches) were largely removed by supplementation so that the supplemented plants came to resemble those grown in full daylight, particularly in the glasshouse experiments. The results highlight the Importance of the radiation environment at the base of the canopy in the morphogenetic responses of plants to putative competition, and the data are consistent with the hypothesis that responses are communicated acropetally along the stolon.  相似文献   

IMAGING DIAGNOSIS—EQUINE NASAL SEPTAL THICKENING DUE TO CHRONIC CHONDRITIS     

AJAY SHARMA  MARGRET S. THOMPSON  LAUREN V. SCHNABEL  ASLI METE  RICHARD HACKETT 《Veterinary radiology & ultrasound》2010,51(1):65-68

We describe the use of computed tomography (CT) in a 6-year-old mare with upper airway obstruction due to an abnormally thick nasal septum. Upon CT imaging, multifocal, expansile cyst-like lesions were detected in the nasal septum. The histopathologic diagnosis was chronic dissecting chondritis. Resection of the abnormal nasal septum resulted in resolution of the clinical signs.  相似文献   

Bioavailability and pharmacokinetics of metoclopramide in cattle   总被引：1，自引：0，他引：1  

R. D. JONES  K. M. MIZINGA  F. N. THOMPSON  J. A. STUEDEMANN  J. M. BOWEN 《Journal of veterinary pharmacology and therapeutics》1994,17(2):141-147

The bioavailability of metoclopramide was investigated in three steers following administration of 8 mg/kg by the oral, abomasal (cannula), and intravenous routes, using a Latin square design. The mean (± SD) oral and abomasal bioavailabilitles were 51.3 ± 30.7% and 76.2 ± 15.5%, respectively. The mean value for clearance ( C1 ) was 20.1 ± 5.9 ml/min and the volume of distribution ( V _d) was 0.51 ± 0.19 1/kg. Additionalpharmacokmetic parameters for metoclopramide were determined following intravenous administration to seven cows. A predominate two-compartment model of distribution was found in six cows with a t _1/2α harmonic mean of 24.2 min and a range of 11.2–72.4 min, a t _1/2β harmonic mean of 53.1 min and a range of 31.1–134.1 min, a Cl of 42.2 ± 8.7 ml/min, and a V _d of 2.1 ± 0.8 1/kg. To better define the relationship between metoclopramide concentration and release of prolactin, a treatment-by-subjects infusion study was conducted in which four different loading doses followed by constant infusion were used. A steady-state metoclopramide concentration ( MCP _ss) of 8.8 ± 2.6 ng/ml was associated with a three-fold elevation of prolactin to a mean value of 12.1 ± 3.1 ng/ml in six yearling steers. Steady state serum prolactin concentrations ( PRL _ss) did not rise significantly above 23.3 ± 6.9 ng/ml, even when MCP _ss reached a concentration of 518.5 ±151.2 ng/ml. The short half-life, moderate V _d, low minimum pharmacologically effective concentration, and rapid C1 found for metoclopramide in cattle in this study, suggest that a continuous release device could potentially be useful in the application of this drug in the prevention and treatment of fescue toxicosis.  相似文献   

Canine respiratory virus infections   总被引：2，自引：0，他引：2  

N. G. WRIGHT  H. THOMPSON  H. J. C. CORNWELL  D. TAYLOR 《The Journal of small animal practice》1974,15(1):27-35

The aetiology and pathogenesis of canine respiratory disease is complex. Current research has implicated a number of viruses in this important disease problem. Distemper virus, two adenoviruses (ICH virus and A26/61 virus), herpesvirus and reovirus have all been isolated from the respiratory tract of dogs and are all capable of causing respiratory lesions in experimental animals. The general features of each of these virus infections are discussed.
Résumé. L'étiologie et la pathogenèse des maladies respiratoires chez le chien est complexe. Une recherche en cours a impliqué un nombre de virus dans cette maladie qui pose un problème important. Le virus de la maladie du jeune âge chez le chien, les adénovirus twp (le virus ICH et le virus A 26/61), le virus de l'herpts et le réovirus ont été tous isolés des voies respiratoires de chiens et sont tous susceptibles de causer des lesions respiratoires chez des animaux expérimentaux. On discute des traits généraux de chacune de ces infections par virus.
Zusammenfassung. Die Ätiologie und Pathogenese von Hunde-Atmungskrankheiten ist komplex. Gegenwärtige Forschung hat eine Reihe von Viren mit diesem wichtigen Krankheitsproblem in Verbindung gebracht. Staupevirus, twp Adenovirus (ICH Virus und A26/61 Virus), Herpesvirus und Reovirus wurden alle vom Luftweg von Hunden isoliert und sind alle fähig Atemläsionen in Versuchstieren zu verursachen. Die allgemeinen Merkmale von diesen Virusinfektionen wurden erörtet.  相似文献   

Anorexia and progressive weight loss in long-term feeding experiments with sheep     

K. H. WALKER  J. M. THOMPSON  R. F. BAYFIELD  D. PERRY 《Australian veterinary journal》1984,61(6):193-194

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SPECIATION OF ECHINOCOCCUS GRANULOSUS IN AUSTRALIA RESEARCH AIMS AND AN APPEAL FOR ASSISTANCE     

R. C. A. THOMPSON 《Australian veterinary journal》1978,54(1):37-37

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Unusual pathological changes in a case of fowl listeriosis     

THOMPSON CH 《American journal of veterinary research》1954,15(54):130-132

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Toxicity of various enzymes when inoculated intracerebally into mice     

THOMPSON SW 《The Cornell veterinarian》1957,47(2):326-334

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Johne's disease in sheep   总被引：1，自引：0，他引：1  

J. T. SEAMAN  D. R. THOMPSON 《Australian veterinary journal》1984,61(7):227-229

SUMMARY Johne's disease was identified in sheep flocks on 6 farms in one area of the central tablelands of New South Wales. The sources of infection were not determined and no common source of all infections was identified. The disease was not diagnosed in cattle that were run on 4 of the farms.  相似文献   

Identification of a nonpathogenic Erwinia amylovora guaB mutant     

J. A. EASTGATE  L. THOMPSON  J. MILNER  R. M. COOPER  C. E. POLLITT  & I. S. ROBERTS 《Plant pathology》1997,46(4):594-599

A nonpathogenic Erwinia amylovora transposon mutant that has an insertion in the gua B gene was isolated. The mutation results in a nutritional requirement for guanine or xanthine, and loss of ability to produce ooze on immature pear fruit and to cause symptoms in the apple seedling assay. The mutant expressed other known virulence determinants including extracellular polysaccharide and had an intact hrp/dsp cluster. In addition it was able to grow in host tissue, although the population size in planta was maintained at a considerably lower level than that seen with the parent strain. The inability of the Erwinia amylovora gua B mutant to cause disease indicates that levels of guanine in plant tissue are likely to be insufficient to maintain optimal growth via the purine salvage pathway. This, in turn, appears to compromise the ability of the mutant to develop a sufficiently large population size in planta to overcome host defence mechanisms and cause disease symptoms. This indicates that a functional de novo guanine synthetic pathway is important for Erwinia amylovora to grow on plant tissue and cause disease.  相似文献