Characterization of rupture of abdominal artery aneurysm in dairy cattle.     

Catherine G Lamm  Charles L Guard  Hollis N Erb  Bradley L Njaa 《Journal of veterinary diagnostic investigation》2007,19(3):273-278

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The effect of plant growth regulators on somaclonal variation in Cavendish banana (Musa AAA cv. ‘Zelig’)     

Michael W. Bairu  Catherine W. FennellJohannes van Staden 《Scientia Horticulturae》2006

The effect of the type and concentration of plant growth regulators and sub-culturing on somaclonal variation were studied in Cavendish banana cv. ‘Zelig’ obtained from African Biotechnologies Ltd., South Africa. In vitro grown plants at the fourth multiplication cycle were used for the investigation. Auxins (IAA, IBA and NAA) and cytokinins (BA and TDZ) were used to multiply shoots for 10 generations. Bands generated through RAPD-PCR were scored according to whether they were present (1) or absent (0) to determine the extent of somaclonal variation. Results were then analyzed using cluster analysis. The relationship between multiplication rate and somaclonal variation was assessed using correlation analysis. Results indicated that treatments with higher multiplication rates produced more variants; sometimes as high as 72%. Dwarf off-types accounted for 88% of the variation. A dwarf-specific band, about 1500 kb in size, was amplified by the primer OPC-15. The band appeared consistently in normal plants but was absent in all dwarf plants.  相似文献   

Using competition and light estimates to predict diameter and height growth of naturally regenerated beech seedlings growing under changing canopy conditions   总被引：3，自引：0，他引：3  

Collet  Catherine; Chenost  Clement 《Forestry》2006,79(5):489-502

In a naturally regenerated beech (Fagus sylvatica L.) standin northeastern France, five regeneration patches were selectedwith different degrees of canopy closure; the percentage ofabove-canopy light (PACL) ranged between 5 and 45 per cent.The canopy was removed by a storm 2 years later. In order toanalyse the immediate and delayed effects of PACL on seedlingdiameter and height growth, the effects of the light conditionsprevailing before canopy opening on seedling growth measuredbefore and after canopy opening were tested. The effects oflocal density were examined using neighbourhood analysis. Fourdifferent competition indices (CIs) and neighbourhood radiiranging from 10 to 200 cm were tested. Models including PACLand CI accounted for between 56 and 64 per cent of the variationin individual seedling annual diameter or height growth. Localdensity had a strong negative influence on diameter growth anda much smaller influence on height growth. PACL was positivelycorrelated with diameter and height growth before canopy opening.Delayed effects of PACL on height growth were observed justafter canopy opening, but disappeared after 2 years. No delayedeffects of PACL on diameter growth after canopy opening wereobserved.  相似文献   

Growth and mortality in underplanted tree seedlings in response to variations in canopy closure of Norway spruce stands   总被引：2，自引：0，他引：2  

Lof  Magnus; Karlsson  Matts; Sonesson  Kerstin; Welander  Torkel N.; Collet  Catherine 《Forestry》2007,80(4):371-383

Six broadleaved tree species and Picea abies (L.) Karst. wereplanted under spruce plantations of varying densities, in Sweden.Treatments included control (994 stems ha^–1), dense (538stems ha^–1), sparse (294 stems ha^–1) and gap (0stems ha^–1) overstory treatments. There was an increasein height and diameter growth from control to sparse overstorytreatment of all underplanted tree species except for ash (Fraxinusexcelsior L.) and Norway maple (Acer platanoides L.). Site conditionsmay have hampered the growth of these species, as well as wildcherry (Prunus avium L.). Both oak (Quercus robur L.) and sprucehad greater growth in the gap treatment, relative to the othertreatments. Insecticide application did not influence seedlinggrowth or survival. The performance of beech (Fagus sylvaticaL.), lime (Tilia cordata Mill.), spruce and oak was consistentwith shade tolerance ranking. Beech and lime had a very highsurvival rate, even under the densest canopy. The growth andmortality of ash, maple and wild cherry differed significantlyfrom what was expected. This experiment demonstrated significantvariation in interspecific growth and mortality between sevenplanted tree species in relation to canopy density. Correctsite and species selection is crucial when underplanting inshelterwood systems.  相似文献   

Acidic mist reduces foliar membrane-associated calcium and impairs stomatal responsiveness in red spruce     

Borer CH  Schaberg PG  DeHayes DH 《Tree physiology》2005,25(6):673-680

Acidic deposition can leach essential pools of calcium (Ca) directly from plant foliage. Because of the central role of Ca in environmental signal transduction, disruptions of labile foliar Ca pools could impair physiological responses to a variety of environmental stimuli and stressors. We investigated the possibility that acidic mist-induced depletion of membrane-associated Ca (mCa), which is one form of labile Ca, may alter stomatal responsiveness to water stress, a process known to include Ca in signal transduction cascades. Red spruce (Picea rubens Sarg.) seedlings were exposed to either pH 3.0 or pH 5.0 mist treatments for one growing season. Foliar nutrition was assessed following treatments, and declines in stomatal conductance and net photosynthesis were measured on current-year shoots following stem excision. Seedlings exposed to pH 3.0 acidic mist treatments had reduced mCa relative to the pH 5.0 treated seedlings. Seedlings subjected to the pH 3.0 acidic mist treatment exhibited impaired stomatal functions, including a smaller maximum aperture, slower closure and an increased lag time between stomatal closure and photosynthetic decline following experimental water stress. Delayed stomatal closure could undermine desiccation avoidance mechanisms. Previous work has demonstrated that acidic mist treatments deplete mCa in red spruce and impair cold tolerance, with similar effects in other species. The results we present provide further evidence that acidic mist-induced mCa depletion may cause disruption of a broad range of plant stress responses.  相似文献   

Morphological and physiological responses of beech (Fagus sylvatica) seedlings to grass-induced below ground competition     

Coll L  Balandier P  Picon-Cochard C 《Tree physiology》2004,24(1):45-54

We examined morphological and physiological responses of beech (Fagus sylvatica L.) seedlings to grass-induced below ground competition in full-light conditions. Two-year-old beech seedlings were grown during two growing seasons in 160-l containers in bare soil or with a mixture of five grass species widely represented in semi-natural meadows of central France. At the end of the second growing season, beech seedlings in the presence of grass showed significant reductions in diameter and height growth, annual shoot elongation, and stem, root and leaf biomass, but an increase in root to shoot biomass ratio. Grasses greatly reduced soil water availability, which was positively correlated with daily seedling diameter increment. Beech seedlings seemed to respond to water deficit by anticipating stomatal closure. There was evidence of competition for nitrogen (N) by grasses, but its effect on seedling development could not be separated from that of competition for water. By labeling the plants with 15N, we showed that beech seedlings absorbed little N when grasses were present, whereas grasses took up more than 97% of the total N absorbed in the container. We conclude that, even if beech seedlings display morphological and physiological adaptation to below ground competition, their development in full-light conditions may be strongly restricted by competition from grass species.  相似文献   

Optimized methods for obtaining cellulose and cellulose sulfates from birch wood     

Boris N. Kuznetsov  Svetlana A. Kuznetsova  Vladimir A. Levdansky  Alexandr V. Levdansky  Natalia Yu. Vasil’eva  Nikolay V. Chesnokov  Natalia M. Ivanchenko  Laurent Djakovitch  Catherine Pinel 《Wood Science and Technology》2015,49(4):825-843

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Conifer regeneration in managed temperate mixedwood stands: the balance between release and competition     

Catherine Larouche  Martin-Michel Gauthier  Vincent Roy  Donald Blouin 《New Forests》2015,46(3):409-425

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The increasing risk of Lyme disease in Canada     

Catherine Bouchard  Erin Leonard  Jules Konan Koffi  Yann Pelcat  Andrew Peregrine  Neil Chilton  Kateryn Rochon  Tim Lysyk  L. Robbin Lindsay  Nicholas Hume Ogden 《The Canadian veterinary journal. La revue veterinaire canadienne》2015,56(7):693-699

There is an increasing risk of Lyme disease in Canada due to range expansion of the tick vector, Ixodes scapularis. The objectives of this article are to i) raise public awareness with the help of veterinarians on the emerging and expanding risk of Lyme disease across Canada, ii) review the key clinical features of Lyme disease in dogs, and iii) provide recommendations for veterinarians on the management of Lyme disease in dogs.  相似文献   

Interactions between a non glycosylated human proline-rich protein and flavan-3-ols are affected by protein concentration and polyphenol/protein ratio   总被引：1，自引：0，他引：1  

Pascal C  Poncet-Legrand C  Imberty A  Gautier C  Sarni-Manchado P  Cheynier V  Vernhet A 《Journal of agricultural and food chemistry》2007,55(12):4895-4901

Interactions between salivary proline-rich proteins and tannins are involved in astringency, which is one of the most important organoleptic sensations perceived when drinking wine or tea. This work aimed to study interactions between a recombinant human salivary proline-rich protein, IB-5, and a flavan-3-ol monomer, epigallocatechin gallate (EGCG). IB-5 presented the characteristics of natively unfolded proteins. Interactions were studied by dynamic light scattering, isothermal titration microcalorimetry, and circular dichroism. The interaction mechanism was dependent on protein concentration. At low concentrations, a three-stage mechanism was evidenced. Saturation of the interaction sites (first stage) was followed by protein aggregation into metastable colloids at higher EGCG/protein ratios (second stage). Further increasing this ratio led to haze formation (third stage). At low ratios, a disorder-to-order transition of IB-5 structure upon binding was evidenced. At high protein concentrations, direct bridging between proteins and EGCG was observed, resulting in significantly lower aggregation and turbidity thresholds.  相似文献