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Journal of Integrative Plant Biology 2012年第12期54卷 1007-1020页

作者： Jill E.Cairns Ciro Sanchez Mateo Vargas Raziel Ordoez jose luis araus Global Maize Program International Maize and Wheat Improvement Center(CIMMYT)Mexico D.F.Mexico Bioinformatics and Statistics Unit International Maize and Wheat Improvement Center(CIMMYT)Mexico D.F.Mexico Unit of Plant Physiology Department of Plant BiologyUniversity of BarcelonaBarcelonaSpain

To increase maize （Zea mays L.） yields in drought-prone environments and offset predicted maize yield losses under future climates, the development of improved breeding pipelines using a multi-disciplinary approach is essential. Elucidating key growth processes will provide opportunities to improve drought breeding progress through the identification of key phenotypic traits, ideotypes, and donors. In this study, we tested a large set of tropical and subtropical maize inbreds and single cross hybrids under reproductive stage drought stress and well-watered conditions. Patterns of biomass production, senescence, and plant water status were measured throughout the crop cycle. Under drought stress, early biomass production prior to anthesis was important for inbred yield, while delayed senescence was important for hybrid yield. Under well-watered conditions, the ability to maintain a high biomass throughout the growing cycle was crucial for inbred yield, while a stay-green pattern was important for hybrid yield. While new quantitative phenotyping tools such as spectral reflectance （Normalized Difference Vegetation Index, NDVI） allowed for the characterization of growth and senescence patterns as well as yield, qualitative measurements of canopy senescence were also found to be associated with grain yield.

关键词： Climate change drought stress ideotypes maize senescence spectral reflectance.

Phenotyping for Abiotic Stress Tolerance in Maize

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Journal of Integrative Plant Biology 2012年第4期54卷 238-249页

作者： Benhilda Masuka jose luis araus Biswanath Das Kai Sonder Jill E.Cairns International Maize and Wheat Improvement Center(CIMMYT) Unit of Plant Physiology Faculty of BiologyUniversity of Barcelona CIMMYT Km 45 Carretera Mexico-Veracruz

The ability to quickly develop germplasm having tolerance to several complex polygenic inherited abiotic and biotic stresses combined is critical to the resilience of cropping systems in the face of climate change. Molecular breeding offers the tools to accelerate cereal breeding; however, suitable phenotyping proto- cols are essential to ensure that the much-anticipated benefits of molecular breeding can be realized. To facilitate the full potential of molecular tools, greater emphasis needs to be given to reducing the within-experimental site variability, application of stress and characterization of the environment and appropriate phenotyping tools. Yield is a function of many processes throughout the plantcycle, and thus integrative traits that encompass crop performance over time or organization level （i.e. canopy level） will provide a better alternative to instantaneous measurements which provide only a snapshot of a given plant process. Many new phenotyping tools based on remote sensing are now available including non-destructive measurements of growth-related parameters based on spectral reflectance and infrared thermometry to estimate plant water status. Here we describe key field phenotyping protocols for maize with emphasis on tolerance to drought and low nitrogen.

关键词： Drought low nitrogen tolerance maize phenotyping spatial variability.

New Technologies,Tools and Approaches for Improving Crop Breeding

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Journal of Integrative Plant Biology 2012年第4期54卷 210-214页

作者： Parry, Martin A. J. Wang, Jiankang luis araus, jose Rothamsted Res Harpenden Herts England Chinese Acad Agr Sci Beijing 100193 Peoples R China Univ Barcelona Barcelona Spain

Most crops were first domesticated about 13 000 to 11 000 years ago. Humans are dependent on crops for survival, and from the beginnings of agriculture have been energetically involved in developing crops that better serve their needs （Allard 1999）. During the last decades breeding has contributed approximately a 50% contribution to increasing the world＇s food crop production. However, plant breeding only began to adopt a scientific approach in the 1900s, when Mendel＇s hybridization experiment was rediscovered. Mendelian genetics and the development of the statistical concepts of randomJzatJon and replication had considerable impact on plant breeding methods （Hallauer et al. 1988）. In spite of the fact that scientific crop breeding has only existed for one century, it is a discipline that is developing very quickly. The major objective of crop breeding programs is to develop new genotypes that are genetically superior to those currently available for specific environments. To achieve this objective, breeders employ a range of selection methods and technologies （Hallauer et al. 1988; Falconer and Mackay 1996; Allard 1999）.

关键词： PLANT breeding PLANT breeders CLIMATIC changes FOOD security EFFECT of drought on plants PLANT genetics NUCLEOTIDE sequence

Gene expression and physiological responses to salinity and water stress of contrasting durum wheat genotypes

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Journal of Integrative Plant Biology 2016年第1期58卷 48-66页

作者： Salima Yousfi Antonio J.Marquez Marco Betti jose luis araus Maria Dolores Serret Unit of Plant Physiology Department of Plant BiologyFaculty of BiologyUniversity of Barcelona08028Spain Department of Plant Biochemistry and Molecular Biology Faculty of ChemistryUniversity of SevilleSevilla 41012Spain

Elucidating the relationships between gene expression and the physiological mechanisms remains a bottleneck in breeding for resistance to salinity and drought. This study related the expression of key target genes with the physiological performance of durum wheat under different combinations of salinity and irrigation. The candidate genes assayed included two encoding for the DREB（dehydration responsive element binding） transcription factors Ta DREB1 A and Ta DREB2 B, another two for the cytosolic and plastidic glutamine synthetase（Ta GS1 and Ta GS2）, and one for the specific Na^＋/H^＋ vacuolar antiporter（Ta NHX1）. Expression of these genes was related to growth and different trait indicators of nitrogen metabolism（nitrogen content, stable nitrogen isotope composition, and glutamine synthetase and nitrate reductase activities）, photosynthetic carbon metabolism（stable carbon isotope composition and different gas exchange traits） and ion accumulation. Significant interaction between genotype and growing conditions occurred for growth, nitrogen content, and the expression of most *** general terms, higher expression of Ta GS1, Ta GS2,Ta DREB2 B, and to a lesser extent of Ta NHX1 were associated with a better genotypic performance in growth, nitrogen, and carbon photosynthetic metabolism under salinity and water stress. However, Ta DREB1 A was increased in expression under stress compared with control conditions, with tolerant genotypes exhibiting lower expression than susceptible ones.

关键词： Durum wheat (Triticum turgidum ssp. durum) geneexpression nitrogen metabolism salinity stable isotope

Grain yield losses in yellow-rusted durum wheat estimated using digital and conventional parameters under field conditions

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The Crop Journal 2015年第3期3卷 200-210页

作者： Omar Vergara-Diaz Shawn C.Kefauver Abdelhalim Elazab Maria Teresa Nieto-Taladriz jose luis araus Unit of Plant Physiology Department of Plant BiologyFaculty of BiologyUniversity of BarcelonaDiagonal 64508028 BarcelonaSpain National Institute for Agricultural and Food Research and Technology(INIA) Ctra de la Coruna 7.528040Madrid Spain

The biotrophic fungus Puccinia striiformis f. sp. tritici is the causal agent of the yellow rust in wheat. Between the years 2010–2013 a new strain of this pathogen(Warrior/Ambition),against which the present cultivated wheat varieties have no resistance, appeared and spread rapidly. It threatens cereal production in most of Europe. The search for sources of resistance to this strain is proposed as the most efficient and safe solution to ensure high grain production. This will be helped by the development of high performance and low cost techniques for field phenotyping. In this study we analyzed vegetation indices in the Red,Green, Blue(RGB) images of crop canopies under field conditions. We evaluated their accuracy in predicting grain yield and assessing disease severity in comparison to other field measurements including the Normalized Difference Vegetation Index(NDVI), leaf chlorophyll content, stomatal conductance, and canopy temperature. We also discuss yield components and agronomic parameters in relation to grain yield and disease ***-based indices proved to be accurate predictors of grain yield and grain yield losses associated with yellow rust(R2= 0.581 and R2= 0.536, respectively), far surpassing the predictive ability of NDVI(R2= 0.118 and R2= 0.128, respectively). In comparison to potential yield, we found the presence of disease to be correlated with reductions in the number of grains per spike, grains per square meter, kernel weight and harvest index. Grain yield losses in the presence of yellow rust were also greater in later heading varieties. The combination of RGB-based indices and days to heading together explained 70.9% of the variability in grain yield and 62.7% of the yield losses.

关键词： Wheat yellow rust Field phenotyping NDVI Phenology,Puccinia striiformis RGB-based indices Triticum durum

Glyphosate Dissipation in Different Soils Under No-Till and Conventional Tillage

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Pedosphere 2019年第6期29卷 773-783页

作者： Elena OKADA joséluis COSTA Francisco BEDMAR Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET) Balcarce 7620(Argentina Estación Experimental Agropecuaria Balcarce Instituto Nacional de Tecnología Agropecuaria(INTA)Balcarce 7620(Argentina Facultad de Ciencias Agrarias Universidad Nacional de Mar del PlataBalcarce 7620(Argentina

Glyphosate is the most used herbicide in Argentina, accounting for 62% of the commercialized pesticides on the market. It is used as a weed controller in no-till systems, and it is also applied to various genetically modified crops ( e.g., soybean, corn, and cotton). Although it has a high solubility in water, it tends to adsorb and accumulate in agricultural soils. The main objectives of this work were to compare the dissipation of glyphosate and the accumulation of its metabolite aminomethylphosphonic acid (AMPA) over time in three soils from agricultural areas of Argentina under long-term management with no-till (NT) and conventional tillage (CT) practices. There were no differences in dissipation between NT and CT, indicating that the glyphosate-degrading microflora was not modified by the different tillage managements. Moreover, tillage practices did not alter the general soil properties;therefore, glyphosate bioavailability was not affected by NT or CT practice. Forty percent of the applied glyphosate was degraded within the first three days in all soils, indicating a fast initial dissipation rate. However, the dissipation rate considerably decreased over time, and the degradation kinetics followed a bi-exponential (or two-compartment) kinetic model. No differences were found between tillage practices. Dissipation was not related to the microbial activity measured as soil respiration. The fast decrease in the concentration of glyphosate at the beginning of the dissipation study was not reflected in an increase in the concentration of AMPA. The estimated half-lives for glyphosate ranged between 9 and 38 d. However, glyphosate bioavailability decreases over time, as it is strongly adsorbed to the soil matrix. This increases its residence time, which may lead to its accumulation in agricultural soils.

关键词： Aminomethylphosphonic acid Bioavailability Biodegradation Herbicide Metabolite Pesticide Two-compartment kinetic model

Sintering study of Ti6Al4V powders with different particle sizes and their mechanical properties

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International Journal of Minerals,Metallurgy and Materials 2018年第12期25卷 1389-1401页

作者： joséluis Cabezas-Villa joséLemus-Ruiz Didier Bouvard Omar Jiménez Héctor Javier Vergara-Hernández luis Olmos University Michoacana of San Nicolás of Hidalgo IIMMMorelia 58060México University Grenoble Alpes CNRSSIMaPGrenoble 38000France University of Guadalajara Departamento de Ingeniería de ProyectosZapopan 45100México National Technological Institute of Mexico I.T.MoreliaMorelia 58120México University Michoacana of San Nicolás of Hidalgo INICITMorelia 58060México

Ti6Al4V powders with three different particle size distributions(0–20, 20–45, and 45–75 μm) were used to evaluate the effect of the particle size distribution on the solid-state sintering and their mechanical properties. The sintering kinetics was determined by dilatometry at temperatures from 900 to 1260°C. The mechanical properties of the sintered samples were evaluated by microhardness and compression tests. The sintering kinetics indicated that the predominant mechanism depends on the relative density irrespective of the particle size used. The mechanical properties of the sintered samples are adversely affected by increasing pore volume fraction. The elastic Young's modulus and yield stress follow a power law function of the relative density. The fracture behavior after compression is linked to the neck size developed during sintering, exhibiting two different mechanisms of failure: interparticle neck breaking and intergranular cracking in samples with relative densities below and above of 90%, respectively. The main conclusion is that relative density is responsible for the kinetics, mechanical properties, and failure behavior of Ti6 Al4 V powders.

关键词： Ti6Al4V powders dilatometry microhardness sintering kinetics compression failure behavior

Approximating home ranges of humpback and fin whales in Drake Passage and Antarctica

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Advances in Polar Science 2020年第4期31卷 248-257页

作者： joséluis ORGEIRA Facundo ALVAREZ Departamento Biología de los Predadores Tope Instituto Antártico Argentino.Buenos AiresArgentina Programa de pós-graduação em Ecologia e Conservação.Campus de Nova Xavantina.Universidade do Estado de Mato Grosso Brasil

Identifying home ranges—those areas traversed by individuals in their normal foraging,mating,and parenting activities—is an important aspect of cetacean *** these ranges facilitates identification of resource use and *** and humpback whales occur in Antarctica during the austral summer,but information regarding their home ranges is *** opportunistically collected whale sighting data from eight consecutive summer seasons spanning 2010–2017,we approximate the home ranges of humpback and fin whales around Drake Passage(DRA),West of Antarctic Peninsula(WAP),South Shetland Islands(SSI),an area northwest of the Weddell Sea(WED),and around the South Orkney Islands(SOI).Approximate home ranges are identified using Kernel Density Estimation(KDE).Most fin whales occurred north and northwest of the SOI,which suggests that waters near these islands support concentrations of this *** humpback whales were observed around the SSI,but unlike fin whales,their distributions were highly variable in other *** suggests spatial segregation in areas where both species exist such as SOI,SSI,and *** redundancy analysis(pRDA)suggests that the distributions of these species are more affected by spatial variables(latitude,longitude)than by local scale variables such as sea surface temperature and *** study presents a visual approximation of the home ranges of fin and humpback whales,and identifies variation in the effects of space and environmental variables on the distributions of these whales at different spatial scales.

关键词： humpback whale fin whale home range Antarctica Drake Passasge

Effect of Exogenous Melatonin on Seed Germination and Seedling Growth in Melon(Cucumis melo L.) Under Salt Stress

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Horticultural Plant Journal 2019年第2期5卷 79-87页

作者： josé luis Casta?ares Carlos Alberto Bouzo Plant Physiology Laboratory Department of Basic Sciences Universidad Nacional de Luján Laboratory of Research in Physiology and Plant Molecular Biology Facultad de Ciencias Agrarias Universidad Nacional del Litoral

An investigation was carried out to evaluate the effect of different application forms and concentrations of melatonin on germination and initial growth of melon plants in several different salinity conditions. We evaluated germination percentage and growth of seedlings and measured total chlorophyll content, relative electrolyte leakage, peroxidase activity, root viability, proline concentration, relative water content,Na^+/K^+ratio in green parts and K^+leakage from roots. Seed germination percentage under salt stress increased with treatments of 10 and50 μmol·L^(-1) melatonin. Seed treatment and plant watering with melatonin at 50 μmol·L^(-1) improved growth parameters and plants showed higher chlorophyll content as well as better biochemical parameters than non-treated plants. Results suggest that melatonin can alleviate the effect of salt stress during seed germination and first stages of plant development.

关键词： melon melatonin salt stress germination antioxidation

A NEW APPROACH TO SOLVE SYSTEMS OF LINEAR EQUATIONS

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Journal of Computational Mathematics 2001年第4期19卷 445-448页

作者： V á squez, luis V á squez-Poletti, jos é L. Universidad Complutense 西班牙 E-28040 Universidad Pontificia Comillas 西班牙 E-28015

Presents a study which proposed an iterative approach to solve systems of linear equations. Definition of two families of convergent iterative methods; Features of the iterative method; Application of the method to a ... 详细信息

关键词： Iterative method Linear systems Classical dynamics.