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31.
Iohexol has been found to be a safe and radiographically satisfactory myelographic contrast medium in man and some experimental animals. This study has shown it is also suitable for the dog and cat. No adverse side effects were encountered and radiographic quality was good. A random comparison found it superior in radiographic quality to metrizamide. Iohexol is recommended as the contrast medium of choice for small animal myelography. 相似文献
32.
The growth of germ-tubes of Botrytis cinerea at 24°C on leaf discs of six cabbage cultivars taken from heads prior to storage, was directly related to the proportion of whole heads developing rots caused by Botrytis during storage for 6 months at 1–2°C. Dipping heads in iprodione before cold storage substantially reduced losses, particularly in the most susceptible cultivar (Decema Extra). Both leaf disc assays of germ-tube growth and studies of whole heads in store indicated significant and similarly ranked differences in cultivar susceptibility. 相似文献
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34.
Pot‐grown and plantation‐grown Eucalyptus nitens trees (approximately 2 and 3 years old, respect‐ively) were experimentally wounded and inoculated with different fungi and in different seasons. Decay lesion development and defence zones were assessed. Two zones were described, a narrow brown decay interface (interface reaction zone, IRZ) and a diffuse zone beyond this being either pale brown or purple (reaction zone, RZ). The total phenol levels in the reaction zone were determined. Selected phenolics (pedunculagin, tellimagrandin 1, tetragalloylglucose, pentagalloylglucose and catechin) were quantified by liquid chromatography–mass spectrometry (LC–MS). A range of fungi (mainly decay‐causing) were used to inoculate wounds and the results indicated that more extensive decay lesions were generally associated with greater production of soluble phenols in response. Sterile inoculations and weakly aggressive fungi were associated with no or little xylem discoloration, whereas aggressive fungi elicited more discoloration and phenolic accumulation in advance of infection. This indicates that phenol accumulation is not a generalized response to wounding, but a variable response due to the interaction between microorganisms and sapwood. In plantation‐grown trees examined 6 months after wounding, purple reaction zones were commonly associated with large decay lesions. Seasonal differences in decay column area caused by Ganoderma applanatum were not significant 1 month after wounding and inoculation. 相似文献
35.
Sheet Mulching as an Aid to Broadleaved Tree Establishment II. Comparison of Various Sizes of Black Polythene Mulch and Herbicide Treated Spot 总被引:1,自引:0,他引:1
Eight experiments, each having 15 treatments, were established.Sites with clayey, loamy and sandy soils were used. The treatmentsincluded herbicide spots of various sizes up to whole plotskept weed-free; polythene mats of various sizes up to wholeplots (10 x 8 m) covered in polythene; and polythene mats ofvarious sizes with the rest of the weeds within the plot treatedwith herbicide. In each experiment survival or growth or both increased thefurther weeds were kept from the trees. Growth was increasedmost on the sandy site. Survival was increased most in the experimentwhich used poor quality oak plants - from zero in the controltreatment to 63 per cent in the whole-plot polythene treatment.Herbicide spots were generally better than polythene mats whenthe area treated was less than one square metre per tree, butnot so good when larger areas were treated: this is attributedto weeds rooting under the mulches. Growth was increased whenthe weeds around the mulches were killed. Accidental herbicidedamage, voles gnawing the trees from beneath the mulches, andsoil anaerobism on poorly drained sites also influenced theresults. 相似文献
36.
The Importance of Weed Control and the Use of Tree Shelters for Establishing Broadleaved Trees on Grass-Dominated Sites in England 总被引:1,自引:0,他引:1
The results of seven experiments are used to illustrate themechanisms of weed competition and its effects. Studies of soilmoisture tension and foliar nutrient content indicated thatcompetition was primarily for moisture and nutrients reducingthe survival and growth of young trees. These effects are greateron soils with poor moisture retention, or where the climateresults in high soil moisture deficits. To be effective, weedcontrol must eliminate root competition. This can be done bycultivation, herbicides or mulching; cutting weeds above groundlevel is ineffective. Tree shelters accelerate the height growthof young trees and protect them from mammals and herbicide drift. 相似文献
37.
The effects of lenacil, terbacil, chlorthiamid and 2,4,5-T at 100 ppm on carbon dioxide evolution, oxygen uptake and nitrogen transformation in two soils have been investigated for several months in the laboratory. The herbicides had no effect on CO2 output from either Boddington Barn soil (organic carbon content 1.6%, pH 6.1) or Triangle soil (organic carbon content 3.7%, pH 4.8) apart from 2,4,5-T which reduced it sometimes. All the herbicides caused temporary reductions in O2. uptake, but in Triangle soil treated with 2,4,5-T a significant reduction was observed during the second half of the incubation. 2,4,5-T and to a lesser extent chlorthiamid, reduced nitrification in Triangle soil. All the herbicides slightly increased mineralization of nitrogen except 2,4,5-T which had variable effects in Triangle soil. 相似文献
38.
LFC Brito AD Barth NC Rawlings RE Wilde DH Crews Jr PS Mir JP Kastelic 《Reproduction in domestic animals》2007,42(5):502-508
The objective of the present study was to characterize changes in serum metabolic hormones concentrations from 20 weeks before to 20 weeks post-puberty in bulls and to investigate the associations of metabolic hormones concentrations with testicular development. Leptin concentrations increased from 16 weeks before puberty to 8 weeks post-puberty and insulin concentrations increased from puberty to 8 weeks post-puberty. Growth hormone concentrations decreased after 4 weeks post-puberty, whereas IGF-I concentrations increased from 8 weeks before puberty to 8 weeks post-puberty. During this period, testicular growth was accelerated and testosterone secretion increased substantially, without any significant changes in gonadotropin secretion. Monthly circulating concentrations of leptin, IGF-I and insulin accounted for 63% of the variation in scrotal circumference and 59% of the variation in paired testes volume. In conclusion, the secretion of metabolic hormones was not associated with changes in gonadotropins concentrations. Furthermore, the associations of leptin, IGF-I and insulin concentrations with testes size indicated that these hormones might be involved in a gonadotropin-independent mechanism regulating the testicular development in peripubertal bulls. 相似文献
39.
R. I. B. FRANCKI J. W. RANDLES T. HATTA C. DAVIES P. W. G. CHU G. D. McLEAN 《Plant pathology》1983,32(1):47-59
A new virus, subterranean clover mottle virus (SCMoV) was found at several locations in Western Australia in Trifolium subterraneum L. (subterranean clover) with severe disease symptoms. Paiticles of the virus were shown to share many physical properties with members of the sobemo-virus group. However, in addition to the single-stranded RNA of MJ about 1.5 × 106 which is characteristic of sobemoviruses, SCMoV particles also contained circular and linear viroid-like RNAs of two size classes, one about 400 and the other about 300 nucleotides long. At present it is not clear if the two types of viroid-like RNAs are components of the same SCMoV strain or of closely related strains of the virus which are able to confect subterranean clover.
SCMoV was shown to be serologically related to lucerne transient streak virus (LTSV). However, the relationship was remote and whereas most high-titred antisera to LTSV reacted with SCMoV particles, antisera to SCMoV failed to recogaize those of LTSV. Neither SCMoV nor LTSV are serologically related to velvet tobacco mottle virus (VTMoV) or Solanum nodiflorum mottle virus (SNMV). However, particles of all four viruses have many physical and chemical properties in common, including RNA complements consisting of both virus-like and viroid-like RNAs. Because of their affinities and unique RNA complements, we suggest that SCMoV, LTSV, VTMoV and SNMV may warrant inclusion in a new taxonomic group. 相似文献
SCMoV was shown to be serologically related to lucerne transient streak virus (LTSV). However, the relationship was remote and whereas most high-titred antisera to LTSV reacted with SCMoV particles, antisera to SCMoV failed to recogaize those of LTSV. Neither SCMoV nor LTSV are serologically related to velvet tobacco mottle virus (VTMoV) or Solanum nodiflorum mottle virus (SNMV). However, particles of all four viruses have many physical and chemical properties in common, including RNA complements consisting of both virus-like and viroid-like RNAs. Because of their affinities and unique RNA complements, we suggest that SCMoV, LTSV, VTMoV and SNMV may warrant inclusion in a new taxonomic group. 相似文献
40.