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41.
The main goal of this work was to introduce resistance genes for rust, caused by Uromyces appendiculatus, and anthracnose, caused by Colletotrichum lindemuthianum, in an adapted common bean cultivar through marker-assisted backcrossing. DNA fingerprinting was used to select plants genetically closer to the recurrent parent which were also resistant to rust and to race 89 of C. lindemuthianum. DNA samples extracted from the resistant parent (cv. Ouro Negro), the recurrent parent (cv. Rudá), and from BC1, BC2 and BC3 resistant plants were amplified by the RAPD technique. The relative genetic distances in relation to the recurrent parent varied between 9 and 59% for BC1, 7 and 33% for BC2, and 0 and 7% for BC3 resistant plants. After only three backcrosses, five lines resistant to rust and anthracnose with, approximately, 0% genetic distance in relation to the recurrent parent were obtained. These lines underwent field yield tests in two consecutive growing seasons and three of them presented a good yield performance, surpassing in that sense their parents and most of the reference cultivars tested. 相似文献
42.
D. M. Moreira J. C. Carvalho A. G. Goulart T. Tirabassi 《Water, air, and soil pollution》2005,161(1-4):285-297
An Eulerian model and a Lagrangian particle model are used to study the dispersion of a contaminant released from a low source in the Stable Boundary Layer (SBL) using two different turbulence parameterisations. The Eulerian model is based on the solution of the advection–diffusion equation by the Laplace transform technique. The Lagrangian model is based on a generalized form of the Langevin equation. The first parameterisation, Degrazia et al. (2000), is based on Taylor’s statistical diffusion theory and the observed spectral properties, supposes a linear combination between shear and buoyancy turbulence. The second, Hanna (1982), is based on observed spectral properties from Minnesota Planetary Boundary Layer (PBL) observations and is widely used in pollutant dispersion models. Considering that these simulations are in the SBL, the analysis of the results shows a reasonably good agreement between the values computed by the models against the experimental ones for the two turbulence parameterisations. 相似文献
43.
José Julio de Toledo William E. MagnussonCarolina V. Castilho Henrique E.M. Nascimento 《Forest Ecology and Management》2011,262(3):331-338
Tree mortality in Amazonia has been related to regional variation in soil, topography and climatic disturbances, but the magnitude of the effect of these factors on tree mortality at local and mesoscales remains poorly determined. We investigated tree mortality in 72 1-ha permanent plots spanning 64 km2 of tropical moist forest in Reserva Ducke, Manaus, Brazil. Plots were censused three times (2000-2003, 2003-2005, and 2005-2008), resulting in two census intervals. The relationships of soil and topography to tree mortality were dependent on tree size. Small- and medium-sized trees (1 ? dbh < 30 cm) had similar relationships of mortality with soil and topography, while large trees (dbh ? 30 cm) showed different (or no) relationships. The effects of soil and topography on tree mortality also varied temporally. In the second census interval after storms, soil and topography explained about one-fourth of the spatial variation in mortality of small- and medium-sized trees (<30 cm dbh), whereas no effects were detected in the first census interval. In particular, soil fertility was the most important predictor of tree mortality in the study area. Topography alone (altitude and slope) was associated with only 12% of the spatial variation in tree mortality and the magnitude of the effect of soil and topography on tree mortality also increased after storms. In general, plots on more fertile soils, on steep slopes and sandy soils in valleys showed greater tree mortality than those on plateau with well-drained clayey soils. Therefore, disturbance history and tree size should be included when scaling up tree mortality from local to regional scales. As much variation remains unexplained, other landscape features, such as watershed morphology and wind exposure, may be necessary to make more precise predictions on patterns of tree mortality in Central Amazonia. 相似文献
44.
Paula Martins-Lopes José Lima-Brito Sónia Gomes Julieta Meirinhos Luís Santos Henrique Guedes-Pinto 《Genetic Resources and Crop Evolution》2007,54(1):117-128
Thirty Portuguese and eight foreign olive (Olea europaea L.) cultivars were screened using Random Amplified Polymorphic DNA (RAPD) and Inter-Simple Sequence Repeat (ISSR) markers.
Twenty RAPD primers amplified 301 reproducible bands of which 262 were polymorphic; and 17 ISSR primers amplified 204 bands
of which 180 were polymorphic. The percentage of polymorphic bands detected by ISSR and RAPD was similar (88 and 87%, respectively).
The genetic variability observed was similar in the Portuguese and foreign olive cultivars. Seven ISSR and 12 RAPD primers
were able to distinguish individually all 38 olive cultivars. Twenty specific molecular markers are now available to be converted
into Sequence Characterised Amplified Region (SCAR) markers. Relationships among Portuguese and foreign cultivars is discussed. 相似文献
45.
Fernando Shintate Galindo Marcelo Carvalho Minhoto Teixeira Filho Salatiér Buzetti José Mateus Kondo Santini Eduardo Henrique Marcandalli Boleta Willian Lima Rodrigues 《Journal of plant nutrition》2020,43(8):1057-1069
AbstractNew studies are needed to optimize the nitrogen (N) amount that can be applied to utilize the Azospirillum brasilense benefits. In addition, information regarding the interaction between the urease inhibitor and biological nitrogen fixation (BNF) and how they affect the macronutrients accumulation are also needed. We evaluate the effect of N sources and doses associated with A. brasilense regarding the macronutrients accumulation in straw and grains and wheat grain yield in tropical conditions. A randomized block experimental design was used with four replications in a 2?×?5?×?2 factorial arrangement as follows: two N sources (urea and urea with urease enzyme inhibitor NBPT; five N doses (0, 50, 100, 150, and 200?kg ha?1) applied in topdressing; with and without A. brasilense inoculation. We found that an increase in N doses positively influenced the accumulation of macronutrients in straw and grains and the wheat grain yield. N sources have similar effects. Inoculation with A. brasilense increased accumulation of Mg and S in straw and P, Ca, and Mg in grains, regardless of the N dose. The inoculation with A. brasilense associated with 140?kg ha?1 of N increased wheat grain yield. The inoculation can contribute in a more sustainable way to wheat nutrition and optimizing N fertilization. 相似文献
46.
Schellekens M Hoppeler R Perrin A Gomes JV Boiron D Aspect A Westbrook CI 《Science (New York, N.Y.)》2005,310(5748):648-651
We have studied two-body correlations of atoms in an expanding cloud above and below the Bose-Einstein condensation threshold. The observed correlation function for a thermal cloud shows a bunching behavior, whereas the correlation is flat for a coherent sample. These quantum correlations are the atomic analog of the Hanbury Brown Twiss effect. We observed the effect in three dimensions and studied its dependence on cloud size. 相似文献
47.
Luís?Borda-de-águaEmail author Laetitia?Navarro Catarina?Gavinhos Henrique?M.?Pereira 《Landscape Ecology》2011,26(2):253-265
Roads can have drastic impacts on wildlife populations. Although there is wide recognition of the negative impacts caused
by roads and a wealth of practical studies, there is a lack of theoretical work that can be used to predict the impact of
road networks or to implement mitigation measures. Here, using Skellam’s diffusion model, we develop analytic and numerical
approaches to analyze the impact of road networks on the survival of populations. Our models show that the viability of a
population is determined not only by road density but also by the size and shape of patches. Accordingly, we studied the minimum
size of a patch to sustain a population with given diffusion and growth parameters. We provide simple formulas to estimate
the minimum patch size, and illustrate the importance of shape with square and rectangular patches. Our models also allow
the estimation of time to extinction after road construction for a population in a patch smaller than that of the minimum
size. Finally, using numerical computations we illustrate how the spatial arrangement of fences strongly affects both the
equilibrium density and the spatial distribution of populations, and that not all fence layouts are equally effective. We
anticipate that our methods provide a tool to assess the impact of geometrical features of road networks on wildlife and that
they can be used to design mitigation measures to prevent the decline and extinction of populations in an anthropogenically
disturbed landscape. 相似文献
48.
49.
Moreira MM Carvalho AM Valente IM Goncalves LM Rodrigues JA Barros AA Guido LF 《Journal of agricultural and food chemistry》2011,59(14):7654-7658
This paper reports the development of a novel electrochemical assay for xanthohumol (XN) by square-wave adsorptive-stripping voltammetry (SWAdSV) with a hanging mercury drop electrode. The method showed good repeatability (CV < 2%) and linearity (between 10 and 250 μg L(-1)), as well as suitable limits of detection (2.6 μg L(-1)) and quantification (8.8 μg L(-1)). The method was applied for the quantification of this compound in spent hops, and the results obtained were compared with the HPLC-UV method. XN contents determined by the SWAdSV method were 16 ± 1 and 100 ± 4 μg L(-1) for aqueous and methanolic extracts, respectively. The developed new methodology considerably reduces the analysis time, approximately from 25 min (HPLC-UV method) to 7 min, enabling a high sample throughput. In addition, the detection and quantification limits were approximately 5-fold lower than those obtained with the chromatographic method. 相似文献
50.
Piper L. Nelson Andreas Beck Henrique Cheng 《Veterinary journal (London, England : 1997)》2011,187(2):153-164
The transient receptor potential proteins (TRPs) make up a very important family of ion channels responsible for a wide array of cellular functions. Originally identified in the visual system of Drosophila melanogaster, these channels are ubiquitously distributed throughout the mammalian system. The TRP family is divided into seven subfamilies in two groups: the first group comprises TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPN (Drosophila NOMPC) and TRPA (ankyrin). The second group contains TRPML (mucolipin) and TRPP (polycystin).The biophysical characterization of TRPs has revealed significantly different activation mechanisms and selectivity between channels. Functional studies have demonstrated that TRPs are necessary for a number of physiological processes, including sensation (such as taste, smell and temperature), hormone secretion and development. TRPs mediate these effects mainly by controlling the intracellular Ca2+ concentration, which acts as a second messenger. Recent research has linked TRPs to different diseases. This review considers the impact of TRPs on cell physiology and the abnormalities observed with channel dysfunction. 相似文献