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Search Results: 1 - 10 of 245138 matches for " Jorge Alberto;Trejo-López "
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Adaptation traits in dry bean cultivars grown under drought stress
Acosta-Díaz, Efraín;Acosta-Gallegos, Jorge Alberto;Trejo-López, Carlos;Padilla-Ramírez, José Saúl;Amador-Ramírez, Mario Domingo;
Agricultura técnica en México , 2009,
Abstract: drought is the major constraint to common bean (phaseolus vulgaris l.) production in mexico. the objective of this study was to identify physiological and phenological traits related to drought adaptation in common bean. a field experiment was conducted under a rainout shelter at the valley of mexico experimental station near texcoco, state of mexico. eight common bean cultivars from different genetic races and growth cycle and contrasted drought response were tested under drought stress and non-stress. irrigation was withheld 55 days after sowing at the initiation of flowering, to induce the stressed treatment. starting at this day, six consecutive nondestructive samplings were conducted at noon every other day. in each sampling, leaf water potential, stomata conductance and co2 assimilation rate were determined. data on phenology were also recorded. at physiological maturity, seed yield and shoot biomass were measured. harvest index was calculated. all cultivars exhibited a tendency to escape drought effects throughout accelerated reproductive development. this response was of small magnitude in mesoamerican cultivars negro cotaxtla 91 and bat 477 (type iii) and significant in cultivars from the durango race such as pinto zapata, bayo madero and bayo criollo del llano. significant difference among cultivars for stomata control was observed with high sensitivity in bat 477 and seq 12, cultivars from the mesoamerican race and in ica palmar from nueva granada race. bred and distinct cultivars ica palmar (type i) and pinto villa (type iii) from durango race, displayed high photosynthetic rate and harvest index, traits or mechanisms directly related to seed yield under stress and non-stress conditions.
Biomasa acumulada e intercambio gaseoso en maíz proveniente de semilla de diferente tama?o bajo humedad favorable y restringida: (con 3 tablas)
López-Santillán,José Alberto; Castro-Nava,Sergio; Trejo-López,Carlos; Mendoza-Castillo,Ma. Del Carmen; Ortiz-Cereceres,Joaquín;
Phyton (Buenos Aires) , 2004,
Abstract: the germination speed and seedling growth of maize seed of two different sizes was evaluated. to determine the differences in the biomass production during the vegetative stage from different seed size, considering the effects of humidity on seedling physiological status. a larger amount of biomass in endosperm and embryo allowed greater availability of reserves during the later stage of the germination; previous to emergency resulting in a high seedling vigor and a most accumulation of as much radical biomass as aerial during the vegetative stage, the water restriction during the germination and the vegetative stage of these plants caused a decrement of 72,6% in the aerial biomass accumulation in big and small seed plants, due to a diminution from diverse physiological processes such as stomatic conductance, transpiration and photosynthetic rate.
Temperatura alta y estrés hídrico durante la floración en poblaciones de maíz tropical
Rincón-Tuexi,Juan Arnoldo; Castro-Nava,Sergio; López-Santillán,José Alberto; Huerta,Alfredo J; Trejo-López,Carlos; Briones-Encinia,Florencio;
Phyton (Buenos Aires) , 2006,
Abstract: effects of water and high temperature stresses, either separately or in combination, over biomass accumulation, grain yield and its direct components grain number per ear and individual grain weight], as well as harvest index were determined in four tropical maize populations. results indicated that water stress do not significantly affect the studied variables, due to the absence of a severe water stress during flowering. this was the result of the fallen precipitation at this time. the most important factor in this study was high temperature, which significantly reduced all studied variables, except individual grain weight. high temperature stress reduced aerial biomass accumulation in 45%, being the ear the more affected organ (66%). grain yield was also reduced (74%) mainly due to the high loss of grain number per ear. as a result of the decreased aerial biomass accumulation and grain yield, the harvest index was also reduced (52%). all studied maize populations showed susceptibility to high temperature stress during the flowering phenological stage. this resulted in large grain yield and aerial biomass accumulation losses. this response indicated that selection for improving water stress tolerance in these populations does not necessarily imply obtaining simultaneously a greater resistance to high temperature.
Respuesta del pimiento morrón al secado parcial de la raíz en hidroponia e invernadero Response of sweet pepper to partial root drying in hydroponic and greenhouse
Juan Antonio Chamú-Baranda,Anselmo López-Ordaz,Carlos Ramírez-Ayala,Carlos Trejo-López
Revista mexicana de ciencias agrícolas , 2011,
Abstract: La presente investigación, se realizó con el objetivo de evaluar el efecto de dos niveles de humedad residual en el sustrato, bajo la técnica de secado parcial de la raíz sobre el crecimiento, rendimiento, relaciones hídricas e intercambio de gases de plantas de pimiento morrón (Capsicum annuum L.) Cannon F1. El experimento se estableció en 2009, en el Campus Montecillo del Colegio de Postgraduados en Ciencias Agrícolas, México. Los tratamientos se distribuyeron bajo un dise o completamente al azar con cuatro repeticiones y fueron: 1) SPR80-80, con raíz dividida, y humedad residual del sustrato en ambos recipientes ≥80%; 2) SPR80-30, con raíz dividida, y humedad residual del sustrato en uno de los recipientes ≥80% y el otro ≥30% con ciclos de alternancia; y 3) testigo, con sistema radical completo, y humedad residual del sustrato ≥80%. La fertilización se realizó a través del sistema de riego por goteo, con solución nutritiva de Steiner (1984) a un potencial osmótico de -0.046 MPa. Durante el periodo experimental, se midieron variables relacionadas con el crecimiento, rendimiento, relaciones hídricas, intercambio de gases y calidad del fruto sometiéndose al análisis de varianza y prueba de Tukey al 5% de probabilidad. Los resultados obtenidos muestran que las plantas bajo SPR80-30, tuvieron una eficiencia en el uso del agua y fertilizantes 24% mayor, que el tratamiento testigo, además de aumentar los sólidos solubles totales sin alterar significativamente el crecimiento y rendimiento de las plantas. This study was carried out with the purpose of evaluating the effect of two levels of residual humidity on the substrate, using the technique of partially drying the root, on growth, yield, water relations and gas exchange for sweet pepper plants (Capsicum annuum L.) Cannon F1. The experiment was carried out in 2009, in the Montecillo Campus of the Colegio de Postgraduados en Ciencias Agrícolas, Mexico. Treatments were distributed under a design completely at random, with four repetitions as follows: 1) SPR80-80, with a split root and residual humidity of the substrate in both containers ≥80%; 2) SPR80-30, with a split root and residual humidity of the substrate in one of the containers ≥80% and the other ≥30% with alternance cycles; and 3) control, with a complete root system, and a residual humidity of the substrate ≥80%. Fertilization was performed through drip irrigation, with Steiner solution (1984) at an osmotic potential of -0.046 MPa. During the experimental period, variables related to growth, yield, water relations, gas exchange and fruit quality w
Respuesta del pimiento morrón al secado parcial de la raíz en hidroponia e invernadero
Chamú-Baranda, Juan Antonio;López-Ordaz, Anselmo;Ramírez-Ayala, Carlos;Trejo-López, Carlos;Martínez-Villegas, Enrique;
Revista mexicana de ciencias agrícolas , 2011,
Abstract: this study was carried out with the purpose of evaluating the effect of two levels of residual humidity on the substrate, using the technique of partially drying the root, on growth, yield, water relations and gas exchange for sweet pepper plants (capsicum annuum l.) cannon f1. the experiment was carried out in 2009, in the montecillo campus of the colegio de postgraduados en ciencias agrícolas, mexico. treatments were distributed under a design completely at random, with four repetitions as follows: 1) spr80-80, with a split root and residual humidity of the substrate in both containers ≥80%; 2) spr80-30, with a split root and residual humidity of the substrate in one of the containers ≥80% and the other ≥30% with alternance cycles; and 3) control, with a complete root system, and a residual humidity of the substrate ≥80%. fertilization was performed through drip irrigation, with steiner solution (1984) at an osmotic potential of -0.046 mpa. during the experimental period, variables related to growth, yield, water relations, gas exchange and fruit quality were measured, undergoing variance analysis and the tukey test at 5% probability. results show that plants under pdr80-30 were 24% more water and fertilizer efficient than the control treatment, and increased soluble solids without altering the growth and of the plants in a significant manner.
RESPUESTA A ALTOS NIVELES DE ESTRéS HíDRICO EN MAíZ
Carlos Hugo Avenda?o-Arrazate,José Domingo Molina-Galan,Carlos Trejo-López,Cándido López-Casta?eda
Agronomía Mesoamericana , 2008,
Abstract: El objetivo de este trabajo fue comparar la respuesta a la sequía, en términos de crecimiento vegetativo, desarrollo reproductivo y la acumulación de materia seca, de cuatro variedades de maíz sometidas a diferentes niveles de estrés hídrico, en el Colegio de Postgraduados, México durante el a o 2003. Las variedades fueron: Zacatecas 58 original (Zo), Cafi me original (Co), Zacatecas 58 SM19 (Z19) y Cafi me SM16 (C16). Los niveles de sequía se aplicaron cuando el suelo llegó al punto de marchitez permanente, siendo éstos: 4, 10 y 20 días de sequía, seguidos de la aplicación inmediata de un riego de recuperación y riegos continuos hasta la cosecha. El crecimiento se detuvo por efecto de la sequía en las cuatro variedades, pero una vez que se aplicó el riego de recuperación, éste ocurrió de manera progresiva, de tal forma que las plantas sometidas a sequía igualaron y en algunos casos llegaron a superar a las de riego como ocurrió en Z19. El número de días a fl oración y asincronía fue mayor en Z19 y C16 que Zo y Co; en el índice de cosecha, las variedades originales disminuyeron menos que las mejoradas; mientras que, la biomasa fue menos afectada en las variedades mejoradas que en las originales conforme se prolongó el periodo de sequía. Por lo anterior, se concluyó que las variedades mejoradas han desarrollado un mecanismo de resistencia a sequía llamado "latencia"; mediante el cual, las plantas detienen su crecimiento en condiciones extremas de sequía, pero en el momento en que nuevamente hay humedad en el suelo, reinician su desarrollo hasta completarlo.
CONSUMO DE RESERVAS DE LA SEMILLA DE FRIJOL PARA LA EMERGENCIA Y DESARROLLO INICIAL EN DIFERENTES PROFUNDIDADES DE SIEMBRA
Raquel Celis-Velázquez,Cecilia Beatriz Pe?a-Valdivia,Carlos Trejo-López,Juan Rogelio Aguirre-Rivera
Agronomía Mesoamericana , 2008,
Abstract:
Secado parcial de la raíz de jitomate: efectos en la fisiología de la planta y calidad de fruto
López-Ordaz, Anselmo;Trejo-López, Carlos;Pe?a-Valdivia, Cecilia Beatriz;Ramírez-Ayala, Carlos;Tijerina-Chavez, Leonardo;Carrillo-Salazar, José Alfredo;
Agricultura técnica en México , 2008,
Abstract: the aim of this research was to study under greenhouse and hydroponic conditions the effects of two levels of water availability in the substrate of tomato plants (lycopersicon esculentum mill.), upon physiological and quality related characteristics. the trial was conducted in 2003 as follows: may 21th, sowing; july 1st, transplanting; and november 24th, whole plant harvest, respectively. the technique of irrigation followed by partial root zone drying (prd) was used to establish two moisture treatments in the substrate, control (80-80%) and prd (80-30%). the physiological parameters recorded were: leaf area, dry matter weight, plant water relations, and gas exchange, as well as fruit yield and quality (diameter, firmness, total soluble solids, ph and electric conductivity). plants were grown in two plastic bags filled with "tezontle" (volcanic rock) and their root split in two halves and two moisture treatments applied to the substrate, 80-30% (prd) and 80-80% (control)). these treatments were applied at 28 days after transplanting and were maintained throughout the experiment. results indicate that prd and control treatment did not show any significant difference in relation to the physiological parameters recorded; however, the fruit quality traits such as °brix, firmness and electric conductivity increased without affecting fruit yield under prd treatment.
Germinación y crecimiento de alfalfa bajo condiciones salinas
González-Romero, Sara Lucía;Franco-Mora, Omar;Ramírez-Ayala, Carlos;Ortega-Escobar, Héctor Manuel;Quero-Carrillo, Adrián Raymundo;Trejo-López, Carlos;
Revista mexicana de ciencias agrícolas , 2011,
Abstract: in mexico, alfalfa (medicago sativa l.) is used for feeding cattle and has been studied for responses to salt stress in the germination phase; however, only nacl or mannitol and polyethylene glycols have been used in different levels. due to this, the aims of this research were to study the response of alfalfa in the germination stage to the salinity of the arid and semiarid areas in mexico, and to evaluate its effect on the growth of the radicle and aerial section. in order to achieve this, in the salinity lab of the colegio de postgraduados en ciencias agrícolas during 2009, the seeds underwent germination tests in a factorial design of 11 saline solutions at eight doses (0, 2, 4, 8, 11.7, 15, 19 and 28 ds m-1) and three repetitions. it has been observed that salts nahco3 and sodium sulfate had a greater influence on the germination. the salt that had the greatest effect on the radicle growth was nahco3 and sulfate salinity, whereas cacl2 2h2o and sulfate-hydrochloric salts enhanced growth. the growth of the aerial section was more affected than the growth of the radicle. the combination of salts had a positive effect on the germination percentage, the growth of the radicle and aerial section.
Cardiología "basada en la evidencia": aplicaciones prácticas de la epidemiología. II. El uso de biomarcadores
Trejo-Gutiérrez, Jorge F.;López-Jiménez, Francisco;
Archivos de cardiología de México , 2011,
Abstract: the use of biomarkers that show an association with the development of cardiovascular disease needs a careful evaluation in regard to the quality of evidence that establishes their relationship. although observational studies have been paramount to establish the importance of the traditional risk factors, we can only screen and intervene on biomarkers when there is demonstrated benefit in well-designed randomized clinical trials.
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