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RESPUESTA DE Pinus pinceana GORDON A ESTRéS POR SEQUíA Y ALTAS TEMPERATURAS  [cached]
Rodrigo J. Martiu00F1u00F3n-Martu00EDnez,J. Jesu00FAs Vargas-Hernu00E1ndez,Javier Lu00F3pez-Upton,Armando Gu00F3mez-Guerrero
Revista fitotecnia mexicana , 2010,
Abstract: Con el propósito de identificar las posibilidades de adaptación de Pinus pinceana Gordon al estrés ambiental asociado con el cambio climático, se evaluó en invernadero el efecto del estrés hídrico y del estrés por altas temperaturas, sobre el crecimiento y distribución de biomasa en plantas de 12 procedencias o poblaciones de la especie. El dise o experimental incluyó dos ambientes de temperatura con diferencia promedio de 2 °C, y dos niveles de disponibilidad de agua (S0 = potencial hídrico del suelo mayor a -0.5 Mpa; S1 = potencial hídrico del suelo inferior a -1.5 Mpa). Los dos factores ocasionaron una reducción (P 0.05) en el crecimiento del brote, acumulación de biomasa y relación parte aérea-raíz, pero el efecto del estrés hídrico fue dos a tres veces mayor que el de la temperatura. El aumento en temperatura ocasionó mayor engrosamiento del tallo, efecto que fue más notorio al estar en combinación con estrés hídrico. Se encontró una amplia variación entre las procedencias en el potencial de crecimiento y en la asignación de biomasa en respuesta a los factores de estrés, lo que indica plasticidad fenotípica en sus mecanismos de adaptación. En condiciones de estrés, las procedencias de la región norte redujeron más la acumulación de biomasa y la relación parte aérea-raíz, pero produjeron más ramas que las del sur. Estos resultados permiten postular que esta especie tiene posibilidades de adaptarse al cambio climático, si las poblaciones con mejor respuesta al estrés se usan en programas de conservación y de restauración ecológica.
Potencial dendroclimático de Pinus pinceana Gordon en la Sierra Madre Oriental
Santillán-Hernández, Miriam;Cornejo-Oviedo, Eladio H.;Villanueva-Díaz, José;Cerano-Paredes, Julián;Valencia-Manzo, Salvador;Capó-Arteaga, Miguel ángel;
Madera y bosques , 2010,
Abstract: the climate sensitivity of ten populations of pinus pinceana gordon was determined to analyze their potential for climate reconstruction purposes. the p. pinceana populations are distributed along a latitudinal gradient of the sierra madre oriental and for this study are considered as northeast region (zacatecas, coahuila), north-central region (san luis potosi), and central region (hidalgo, queretaro). all populations were dated to the year of the annual growth formation except a population called "el arenalito" in the central region. the youngest trees were found at populations in the central region (mag, tep, and cri); therefore short tree-ring chronologies were developed for these sites. in contrast, for the northeastern region the populations pal and nor had the oldest trees and longer chronologies were developed for these sites. intercorrelation values (0,61 to 0,77), mean sensitivity (0,49 to 0,69), and sign-to noise ratio values (11,72 to 33,64) are considered high for dendrochronological purposes. the statistic parameters derived from the arstan software indicated that p. pinceana is climate sensitive and shows a similar behavior to other conifer species currently used for dendroclimatic studies in northern mexico. response function analysis indicated that the populations located in the northeast and north-central regions significantly responded to the seasonal january-june precipitation (winter-spring seasons), but the central populations did not show a clear response. defining patterns of reduced annual growth are basic to date this species.
Respuesta de Pinus pinceana Gordon a estrés por sequía y altas temperaturas
Marti?ón-Martínez, Rodrigo J.;Vargas-Hernández, Jesús;López-Upton, Javier;Gómez-Guerrero, Armando;Vaquera-Huerta, Humberto;
Revista fitotecnia mexicana , 2010,
Abstract: to identify the potential for adaptability of pinus pinceana gordon to environmental stress associated with climate change, the effect of drought and high temperature stress on growth and biomass allocation in seedlings from 12 provenances of the species was evaluated under greenhouse conditions. the experimental design included two different temperature environments with an average difference of 2 °c, and two levels of water availability (s0 = soil water potential above -0.5 mpa; s1= soil water potential below -1.5 mpa). both factors caused a reduction (p ≤ 0.05) in shoot growth, biomass accumulation and shoot/root ratio, but the effect of water stress was two to three times higher than temperature stress. the increase in temperature caused a greater thickening of the stem, particularly when combined with water stress. a wide variation among provenances in growth potential and biomass allocation was found in response to stress factors, indicating phenotypic plasticity in their adaptation mechanisms. under stress conditions, populations from the northern region showed higher reductions in biomass accumulation and shoot/root ratio, but produced more branches than populations from the southern region. these results allow us to postulate that the species has the potential to adapt to climate change, if populations with best response to the predicted stress levels are used in conservation and ecological restoration programs.
Crecimiento de la raíz en plantas jóvenes de Pinus pinceana Gordon en respuesta a la humedad del suelo
Córdoba-Rodríguez, Diana;Vargas-Hernández, J. Jesús;López-Upton, Javier;Mu?oz-Orozco, Abel;
Agrociencia , 2011,
Abstract: pinus pinceana gordon is an endemic pinyon pine of méxico that grows in semiarid conditions, in isolated populations, along the sierra madre oriental. in order to identify root traits associated with mechanisms of adaptation to water stress conditions, the growth and root morphology in two soil moisture conditions were evaluated in plants of six populations of the species representing a geographical gradient of aridity. the study was conducted on 3-yearold plants under greenhouse conditions, maintaining soil moisture near field capacity (s0) or below 20 % of usable moisture (s1) over a period of 160 d. the restriction of irrigation reduced by 27 % the number of main roots and 51 % of the root biomass below the 15 cm of soil depth, but increased 166 % the number of lateral roots and 83 % the number of fine growing roots and reduced 30 % the shoot/ root ratio. populations of the southern region of the species’ natural range, native of sites with lower aridity index were the most affected by drought in the root growth, particularly the length and volume of the root system. this suggests that different environmental conditions to which this pine is subjected in its natural habitat have promoted an ecotypic and genetic differentiation in growth and root structure that can mitigate effects of adverse events such as drought. this ecotypic differentiation is useful in programs for ecological restoration and conservation of the species.
Composición isotópica de carbono en follaje de Pinus pinceana Gordon sometido a estrés hídrico y térmico
Marti?ón-Martínez, R. Julián;Vargas-Hernández, J. Jesús;Gómez-Guerrero, Armando;López-Upton, Javier;
Agrociencia , 2011,
Abstract: pinus pinceana gordon grows in semiarid conditions in the northeast and central east of méxico. probably it is facing a high risk of disappearing due to increased temperature and drought associated with the climate change forecast. in order to understand the physiological mechanisms in the adaptation of this species to environmental stress conditions and define management options for the conservation and restoration of its natural populations, we studied the variation in carbon isotope composition (δ13c) and in the relative growth rate (rgr) in plants of six populations of p. pinceana subjected to water stress and high temperature under greenhouse conditions. the study populations represented a north-south transect of the natural distribution of the species in mexico. in a factorial experiment, two temperature environments were tested [without changing the temperature (t0) and with an increase of 2 °c (t1) in average temperature] and two levels of humidity [gravimetric content of 50 % (s0) and 12-20 % (sj) soil moisture]. temperature did not influence the value of δ13c, but water stress caused a significant reduction in 13c discrimination (higher δ13c). the effect was greater without stress temperature (to). a significant variation among populations was found in δ13c values. in the two moisture conditions, the northern populations exhibited greater δ13c and higher rgr in height, compared to the southern. the (δ13c values of populations were positively correlated with the rgr in height, but not with biomass accumulation. the analysis of results shows that water use efficiency, estimated indirectly through the value of δ13c, has an important role in the adaptation capacity of p. pinceana populations to the drought conditions it faces at its natural habitat; it is also possible to identify populations of the species with the possibility to adjust to conditions of greater environmental stress associated with climate change.
Adaptabilidad de poblaciones de pinus pinceana en dos suelos  [cached]
Diana Cu00F3rdoba Rodru00EDguez,Jesu00FAs Vargas Hernu00E1ndez,Josu00E9 A. Aru00E9valo Ramu00EDrez
Revista fitotecnia mexicana , 2008,
Abstract: Pinus pinceana se encuentra sometida a fuertes presiones ambientales y antrópicas que la declinan hacia su extinción, y existe poca información ecológica y genética sobre esta especie, en particular sobre las posibles diferencias entre poblaciones en el crecimiento y la distribución de biomasa en plántulas, como mecanismos adaptativos a condiciones ambientales. En este estudio se determinó el patrón de distribución de biomasa y la tasa de crecimiento de la raíz como características adaptativas en 10 poblaciones naturales de este pino provenientes de las regiones norte y sur de la Sierra Madre Oriental de México, establecidas en rizotrones que contenían dos tipos de suelo. Las condiciones del suelo afectaron de manera significativa (P < 0.05) el crecimiento y la asignación de recursos a la raíz. Las plantas de la región sur acumularon más biomasa total que las del norte, pero no hubo diferencias (P = 0.05) entre poblaciones en el patrón de asignación de biomasa. La especie mostró amplia plasticidad fenotípica en el crecimiento de raíz en respuesta a las condiciones edáficas, lo cual puede ser un mecanismo evolutivo para aprovechar las esporádicas condiciones ambientales favorables en su hábitat natural
Afinidades en la flora genérica de pi onares del norte y centro de México: un análisis fenético Floristic affinities of the generic flora of pinyon pines of northern and central Mexico: a phenetic analysis  [cached]
Mario Luna-Cavazos,Angélica Romero-Manzanares,Edmundo García-Moya
Revista mexicana de biodiversidad , 2008,
Abstract: Mediante un análisis de clasificación fenética, se discuten las afinidades en la flora genérica de los pi onares mexicanos. El estudio se sustentó en el registro de 438 géneros de plantas vasculares de 32 pi onares mexicanos caracterizados por distintas especies como Pinus cembroides, P. johannis, P. maximartinezii, P. monophylla, P. quadrifolia, P. nelsonii, P. culminicola y P. lagunae. Se elaboró una matriz de datos presencia/ausencia de los géneros en los 32 pi onares, cada uno de los cuales se consideró como una Unidad Geográfica Operativa. Se estimaron 2 índices de semejanza entre las comunidades pi oneras, y después se agruparon mediante el procedimiento UPGMA; los grupos formados se representaron en un dendrograma. Los pi onares se relacionaron, en general, por cercanía geográfica y por su localización en una misma provincia fisiográfica. Los pi onares de Baja California caracterizados por P. quadrifolia formaron un grupo compacto, lo mismo que aquellos de P. cembroides de Chihuahua y de P. maximartinezii de Zacatecas. En el grupo de San Luis Potosí se conjuntaron comunidades de P. cembroides y de P. johannis; mientras que las propias de P. nelsonii no formaron un grupo coherente; los pi onares del suroeste de Coahuila están muy relacionados, pero tienen diferencias con los de más al norte de este estado. El pi onar de P. culminicola de Nuevo León es el más diferente de las otras comunidades de pi oneros. Using phenetic classification, we analyze the similarity of the generic flora of Mexican pinyon pine forests. Methods included records of 438 genera of vascular plants from 32 communities of pinyon pines such as Pinus cembroides, P. johannis, P. maximartinezii, P. monophylla, P. quadrifolia, P. nelsonii, P. culminicola, and P. lagunae. A matrix of presence/absence of genera in 32 communities was performed, and 2 indices of similarity between communities were estimated; we then applied UPGMA to classify the communities in groups, and finally these groups were represented by a dendrogram. In general, the communities were grouped by geographic area and by pinyon pine species, as well as location in the same physiographic province. It was observed that pinyon pine communities of Baja California with P. quadrifolia formed a close group, as well as the P. cembroides communities of Chihuahua and P. maximartinezii of Zacatecas. One group of San Luis Potosí included P. cembroides and P. johannis. Pinus nelsonii communities did not form a coherent group. Those of southwestern Coahuila were cosely related, but they were different from the pinyon pines in t
Afinidades en la flora genérica de pi?onares del norte y centro de México: un análisis fenético
Luna-Cavazos, Mario;Romero-Manzanares, Angélica;García-Moya, Edmundo;
Revista mexicana de biodiversidad , 2008,
Abstract: using phenetic classification, we analyze the similarity of the generic flora of mexican pinyon pine forests. methods included records of 438 genera of vascular plants from 32 communities of pinyon pines such as pinus cembroides, p. johannis, p. maximartinezii, p. monophylla, p. quadrifolia, p. nelsonii, p. culminicola, and p. lagunae. a matrix of presence/absence of genera in 32 communities was performed, and 2 indices of similarity between communities were estimated; we then applied upgma to classify the communities in groups, and finally these groups were represented by a dendrogram. in general, the communities were grouped by geographic area and by pinyon pine species, as well as location in the same physiographic province. it was observed that pinyon pine communities of baja california with p. quadrifolia formed a close group, as well as the p. cembroides communities of chihuahua and p. maximartinezii of zacatecas. one group of san luis potosí included p. cembroides and p. johannis. pinus nelsonii communities did not form a coherent group. those of southwestern coahuila were cosely related, but they were different from the pinyon pines in the north of this state. pinus culminicola communities of nuevo león were the most different with respect to others.
Multiplicación in vitrodel Pi?ón Azul Pinus maximartinezii (Rzedowski)
Ojeda-Zacarías,Ma del Carmen; Luna-Olvera,Hugo A; Morales-Ramos,Lilia H; Verde-Star,María J; Torres-Cepeda,Teresa E; Pereyra-Alférez,Benito; Iracheta- Donjuan,Leobardo; Olivares-Sáenz,Emilio; Salazar-Sáenz,Raúl; Cárdenas-Cerda,Elizabeth;
Phyton (Buenos Aires) , 2006,
Abstract: pinus maximartinezii (rzedowski) es una especie endémica en peligro de extinción, confinada a una población de aproximadamente 2000 a 2500 árboles maduros en una superficie de 400 ha. en estos casos, es necesario establecer técnicas de propagación que permitan incrementar la disponibilidad del material vegetativo. el objetivo de este trabajo fue desarrollar un protocolo para la multiplicación in vitro de pinus maximartinezii por medio de organogénesis. embriones cigóticos y cotiledones obtenidos de semillas maduras fueron colocados en los medios de cultivo dcr y gd adicionados con 0.3 mgl-1 y 0.5mgl-1 de bap; 0.01 mgl-1 de naa, permaneciendo por 6 semanas en condiciones de 26°c ± 2°c y un fotoperíodo de 16 h luz y 8 h oscuridad. posteriormente los explantes fueron transferidos a los medios de cultivo (dcr y gd) sin reguladores de crecimiento a intervalos de 15 días, durante 6 semanas. en la siguiente etapa (alargamiento de yemas), la variable evaluada fue número de explantes con yemas. por último los explantes fueron transferidos a los mismos medios de cultivo sin reguladores de crecimiento, adicionados con 0.1% de carbón activado, permaneciendo por 8 semanas; evaluándose posteriormente el número de brotes por embrión. los análisis de varianza mostraron diferencia significativa en medios de cultivo y concentración de reguladores de crecimiento.
Is the energy density of the ground state of the sine-Gordon model unbounded from below for beta^2 > 8 pi ?  [PDF]
M. Faber,A. N. Ivanov
Mathematics , 2002, DOI: 10.1088/0305-4470/36/28/312
Abstract: We discuss Coleman's theorem concerning the energy density of the ground state of the sine-Gordon model proved in Phys. Rev. D 11, 2088 (1975). According to this theorem the energy density of the ground state of the sine-Gordon model should be unbounded from below for coupling constants beta^2 > 8 pi. The consequence of this theorem would be the non-existence of the quantum ground state of the sine-Gordon model for beta^2 > 8 pi. We show that the energy density of the ground state in the sine-Gordon model is bounded from below even for beta^2 > 8 pi. This result is discussed in relation to Coleman's theorem (Comm. Math. Phys. 31, 259 (1973)), particle mass spectra and soliton-soliton scattering in the sine-Gordon model.
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