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排序方式: 共有352条查询结果,搜索用时 31 毫秒
271.
272.
HongLing LIU Yong TAN Monika NELL Karin ZITTER-EGLSEER Chris WAWSCRAH Brigitte KOPP ShaoMing WANG Johannes NOVAK 《干旱区科学》2014,6(2):186-194
Arbuscular mycorrhizal(AM)fungi penetrate the cortical cells of the roots of vascular plants,and are widely distributed in soil.The formation of these symbiotic bodies accelerates the absorption and utilization of mineral elements,enhances plant resistance to stress,boosts the growth of plants,and increases the survival rate of transplanted seedlings.We studied the effects of various arbuscular mycorrhizae fungi on the growth and development of licorice(Glycyrrhiza glabra).Several species of AM,such as Glomus mosseae,Glomus intraradices,and a mixture of fungi(G.mosseae,G.intraradices,G.cladoideum,G.microagregatum,G.caledonium and G.etunicatum)were used in our study.Licorice growth rates were determined by measuring the colonization rate of the plants by the fungi,plant dry biomass,phosphorus concentration and concentration of secondary metabolites.We established two cloned strains of licorice,clone 3(C3)and clone 6(C6)to exclude the effect of genotypic variations.Our results showed that the AM fungi could in fact increase the leaf and root biomass,as well as the phosphorus concentration in each clone.Furthermore,AM fungi significantly increased the yield of certain secondary metabolites in clone 3.Our study clearly demonstrated that AM fungi play an important role in the enhancement of growth and development of licorice plants.There was also a significant improvement in the secondary metabolite content and yield of medicinal compounds from the roots. 相似文献
273.
274.
Campylobacter jejuni is one of the leading causes of sporadic food-borne bacterial disease in humans. In intensive poultry and pig rearing systems the use of oral antibiotics is essential to maintain health. Consequently, there is a high risk for the thermophilic Campylobacter jejuni and C. coli resident in the intestinal tract of food animals to develop resistance to commonly used antibiotics. Contamination of meat or eggs with pathogenic strains of resistant Campylobacter could, therefore, result in a form of campylobacteriosis in humans that is difficult to treat. The aim of this investigation was to determine the antimicrobial susceptibility of thermophilic Campylobacter spp. isolated from pigs and poultry by the broth microdilution minimum inhibitory concentration (MIC) test. A total of 482 samples from the Western Cape and Gauteng provinces was collected and analysed. Thirty-eight Campylobacter isolates were obtained. Analysis of data revealed that C. jejuni strains mainly of poultry origin were more resistant to the fluoroquinolones, macrolides and tetracyclines and the C. coli strains were more resistant to the macrolides and lincosamides. Multi-resistance was also detected in 4 Campylobacter strains from the Western Cape. With the exception of tetracyclines, strains from high health Gauteng broiler farms were susceptible to antibiotics used to treat Campylobacter infections. 相似文献
275.
Dominique This Jonathan Comstock Brigitte Courtois Yunbi Xu Nourollah Ahmadi Wendy M. Vonhof Christine Fleet Tim Setter Susan McCouch 《Rice》2010,3(1):72-86
Carbon isotope discrimination (?13C) is considered as an index of leaf-level water use efficiency, an important objective for plant breeders seeking to conserve water resources. We report in rice a genetic analysis for ?13C, leaf structural parameters, gas exchange, stomatal conductance, and leaf abscisic acid (ABA) concentrations. Doubled haploid and recombinant inbred populations, both derived from the cross IR64 × Azucena, were used for quantitative trait locus (QTL) analysis following greenhouse experiments. ?13C QTLs on the long arms of chromosomes 4 and 5 were colocalized with QTLs associated with leaf blade width, length, and flatness, while a QTL cluster for ?13C, photosynthesis parameters, and ABA was observed in the near-centromeric region of chromosome 4. These results are consistent with phenotypic correlations and suggest that genetic variation in carbon assimilation and stomatal conductance contribute to the genetic variation for ?13C in this population. 相似文献
276.
Thierry Koumbi-Mounanga Daniela Tudor Brigitte Leblon Kevin Groves Paul A. Cooper Tony Ung 《Wood material science & engineering》2018,13(4):204-221
A combination of statistical techniques of analyses were used to evaluate the potential of International Commission on Illumination (CIE) lightness (L*), redness (a*) and yellowness (b*) colour space system and near-infrared spectroscopy (NIRS) to assess surface changes in relation with progressive decay of beech (Fagus grandifolia Ehrh.) by wood-inhabiting lignicolous fungi Inonotus hispidus, Trametes versicolor and Xylaria polymorpha. pH effects based modelling predictions of beech earlywood and latewood tissues were also included. Multivariate analysis techniques included response surface optimization, sample-specific standard error of prediction (SEP) method and projection to latent structures partial least squares (PLS) regression. Strong statistical relationships were derived for pH predictions with R2 values ranged: from 0.77 to 0.84 for I. hispidus; from 0.77 to 0.84 for T. versicolor and from 0.83 to 0.91 for X. polymorpha. R2 values for CIE-based L*a*b* colour space measurements ranged: from 0.43 to 0.69 (L*), 0.66 to 0.76 (a*), 0.42 to 0.53 (b*) for I. hispidus; from 0.59 to 0.69 (L*), 0.69 to 0.79 (a*), 0.64 to 0.79 (b*) for T. versicolor; and from 0.51 to 0.75 (L*), 0.89 to 0.94 (a*), 0.85 to 0.89 (b*) for X. polymorpha. Multivariate technical analysis (response surface analysis, sample-specific SEP, PLS regression) of CIE L*a*b* system and NIRS results should be able to characterize pH effects and surface changes of wood spalted by lignicolous fungi as a quick and reliable non-destructive method relevant to wood-spalting concerns and the forest products industry. 相似文献
277.
Jacques Ranger Pascal Bonnaud Olivier Bouriaud Dominique Gelhaye Jean-François Picard 《Annals of Forest Science》2008,65(3):303-303
278.
Brigitte Dorn Hans-Rudolf Forrer Stéphanie Schürch Susanne Vogelgsang 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(1):51-61
The Fusarium species complex of maize kernels and stem pieces as well as mycotoxin contamination of commercial grain maize hybrids for
animal feed were evaluated in Switzerland. Throughout 2 years, natural Fusarium infection varied significantly between the years and the locations and it ranged from 0.4% to 49.7% for kernels and from
24.2% to 83.8% for stem pieces. Using the agar plate method, 16 different Fusarium species were isolated from kernels and 15 from stem pieces. The Fusarium species composition, prevalence and impact differed between the north and the south and between kernel and stem piece samples.
The dominant species on kernels in the north were F. verticillioides (32.9%), F. graminearum (31.3%), F. proliferatum (7.3%) and F. crookwellense (7.1%), in the south F. verticillioides (57.1%), F. subglutinans (24.6%), F. proliferatum (14.8%) and F. graminearum (1.5%) and on stem pieces F. equiseti (36.0%), F. verticillioides (20.1%), F. graminearum (9.5%), F. crookwellense (6.2%) and F. subglutinans (6.2%). In the south, fumonisin concentration of most hybrids exceeded guidance values for animal feed. Other Fusarium species isolated were F. avenaceum, F. culmorum, F. oxysporum, F. poae, F. sambucinum, F. semitectum, F. sporotrichioides, F. solani, F. tricinctum and F. venenatum. Maize hybrids varied in their susceptibility to Fusarium infection. Because of the high diversity of Fusarium species encountered in Switzerland representing a high toxigenic potential, we propose to screen maize hybrids for resistance
against various Fusarium species and examine maize produce for several mycotoxins in order to ensure feed safety. 相似文献
279.
The feasibility of identifying internal wood characteristics in computed tomography (CT) images of black spruce was investigated
using two promising classifiers: the maximum likelihood classifier (MLC) and the back propagation (BP) artificial neural network
(ANN) classifier. Nine image features including one spectral feature (gray level values), a distance feature, and seven textural
features were employed to develop the classifiers. The selected internal wood characteristics to be identified included heartwood,
sapwood, bark, and knots. Twenty cross-sectional CT images of a black spruce log were randomly selected to develop the two
classifiers. The results suggest that both classifiers produced high classification accuracy. Compared with the MLC classifier
(80.9% overall accuracy), the BP ANN classifier had better classification performance (97.6% overall accuracy). Moreover,
statistical analysis reveals that the heartwood of the black spruce log used in this study is the easiest to identify by either
classifier compared with the other three log features. The results also suggest that the separability of one wood characteristic
from the other wood characteristics in black spruce CT images is mainly related to moisture content. 相似文献
280.