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Search Results: 1 - 10 of 12144 matches for " Javier Figueroa "
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Texture of Chanco cheese: Projection of a sensory map based on multivariate analysis
Leiva,Javier; Figueroa,Heriberto;
Ciencia e investigación agraria , 2010, DOI: 10.4067/S0718-16202010000100008
Abstract: the aim of the study is to evaluate, by using sensory methods, chanco cheese texture by means of quantitative descriptive analysis to project a sensory map based on multivariate analysis. samples of chanco cheese (two different commercial brands) were used. sensory evaluation was undertaken by a trained panel (n = 13), using quantitative descriptive analysis. the sensory profle includes the properties of springiness, hardness, friability, deformability, adhesiveness and cohesiveness. sensory scales from one to seven were used to express the intensity perceived for each property. based on the results, it was possible to observe the formation of a main group, comprising of cohesiveness, friability, springiness and adhesiveness. other groupings were formed with hardness and deformability. from the results, it can be concluded that the sensory properties shown in the chanco cheese sensory map provide information with regard to the solid state (hardness, deformability, friability) and fuidity (cohesiveness, adhesiveness, springiness) of the cheese. the map can serve as a practical tool for the evaluation of sensory properties of texture in quality control and may also be applied in terms of products development.
Seed germination responses in a temperate rain forest of Chiloé, Chile: effects of a gap and the tree canopy
Figueroa,Javier A; Hernández,Juan F;
Ecolog?-a austral , 2001,
Abstract: this study determined germination responses of 19 species, including trees, shrubs, vines, and herbs, under natural gap and non-gap conditions, in a secondary forest in chiloé island, southern chile, in order to assess if there is any association between the habitat where the seedlings of these plant species occur and their germination requirements. statistical differences in percentage seed germination were detected in six species in a gap habitat compared to the understory. five forest edge species (embothrium coccineum, escallonia rubra, gunnera tinctoria, nertera granadensis and rhaphithamnus spinosus) presented greater germination success in the canopy gap, while only one forest interior species (myrceugenia planipes) germinated to a lesser extent in the gap. percentages of seed germination were not statistically different between the two habitats neither in the remaining 10 edge species (gaultheria mucronata, luma apiculata, myrceugenia parvifolia, tepualia stipularis, among others) nor in the 3 forest interior species studied (luzuriaga radicans, mitraria coccinea, and myrceugenia ovata var. ovata). thus, there is no strong evidence of any association between the habitats where seedlings of these plant species grow and their germination requirement.
Seed germination of species of the Juan Fernández archipiélago under laboratory conditions
Cuevas,Jaime G; Figueroa,Javier A;
Gayana. Botánica , 2007, DOI: 10.4067/S0717-66432007000100007
Abstract: the juan fernández islands contain one of the world's most interesting floras. however, their conservation status is fragile due to direct and indirect human activities. with the aim of contributing to the conservation of the native species of these islands, germination trials have been performed under laboratory conditions. we studied the germination patterns and characteristics of 25 taxa of the archipelago, at temperatures between 15°c and 25°c, with 12.5 h. of photoperiod. thirty-five percent of the studied species germinated immediately (within the first month after sowing), while 50% had a delayed germination. three species did not germinate. regarding the germination pattern, nine taxa (53%) germinated synchronously (3 90% of seeds germinated within a month after the first germination), while the remaining 47% germinated asynchronously. most species showed a high germinative potential (350% of germination). generally, the germination results were good for most species assayed, with few species requiring special treatments as scarification. for each species, the pre-germinative treatments, germination characteristics and patterns are detailed and discussed in relation to other published antecedents
Efecto de herbívoros y patógenos en la sobrevivencia y crecimiento de plántulas en un fragmento del bosque templado húmedo de Chiloé, Chile
FIGUEROA,JAVIER A.; CASTRO,SERGIO A.;
Revista chilena de historia natural , 2000, DOI: 10.4067/S0716-078X2000000100015
Abstract: the physical conditions of the environment, the attack of pathogen microorganisms, defoliating invertebrates and herbivores may affect the growth and survival of woody plant seedlings. seedling growth, survival, proportion of damaged individuals by herbivores and pathogens, and the effect of these damages on seedling growth and survival were evaluated in this work. seedling mortality was greater during summer. two thirds of all seedlings presented some type of aggression when monitoring phase was over (11 months). seedlings with cotyledons presented greater proportion of healthy individuals. seedlings without cotyledons presented greater proportion of damaged individuals. the proportion of damaged individuals differed among species. isolated seedlings of amomyrtus luma presented greater proportion of damaged individuals. isolated seedlings of podocarpus nubigena presented same proportion of damaged and healthy individuals. seedlings of amomyrtus luma grouped with conspecifics presented greater proportion of healthy individuals than isolated seedlings of the same species. seedlings of podocarpus nubigena grouped were all damaged. on the other hand, mean shoot growth during the monitoring phase approached 12 mm in 11 months. it was not affected by sanitary state of the seedling. 62% of the seedling survived 11 months. 72% of the seedlings of podocarpus nubigena survived the end of the monitoring phase, while 55% of the seedling of amomyrtus luma survived. however, there are not significant differences in the seedling survival among species, between seedlings with and without cotyledons, and between healthy and damaged seedlings, to exception of the seedlings of amomyrtus luma when they were not distinguished by age. in this last case survived a greater proportion of damaged seedlings of amomyrtus luma. results in the context of known defense theories in plants were discussed
Latencia y banco de semillas en plantas de la región mediterránea de Chile central
FIGUEROA,JAVIER A.; JAKSIC,FABIAN M.;
Revista chilena de historia natural , 2004, DOI: 10.4067/S0716-078X2004000100016
Abstract: seed banks on mediterranean regions display characteristics that distinguish them from the seed banks of other regions. a seed bank is the concentration of viable propagules buried in the soil for variable periods of time. seed banks in the chilean matorral are chiefly transient and functionally similar to seed banks in other mediterranean ecosystems not disturbed by fire, except for those of australia. a transient seed bank is that composed of seeds that cannot survive in the upper levels of the soil for more than 1 year. the density of herb seeds in the chilean matorral soil is one of the highest among mediterranean ecosystems anywhere in the world, and a large proportion of these seeds is made up of seeds without dormancy that germinate easily, particularly annual grasses. with respect to the dormancy mechanisms that may be responsible for the behavior of these seeds stored in the transient bank, our analysis revealed the following germination syndromes: (1) species whose seeds must be stratified in cold due to the presence of physiological dormancy (particularly introduced herbs), (2) species whose seeds must be scarified with acids or mechanical means due to the presence of physical dormancy (mainly native woody species) and, (3) species that present physiological dormancy and need heat stratification to activate germination (both native and introduced species). these syndromes determine that the timing of germination in central chile has an autumn and an early spring phase. besides, there is absence of sporadic germination syndromes for the components of a persistent seed bank. we propose a structural and functional model of the seed bank for the matorral of central chile that should be enriched with future research
The effect of heat and smoke on the emergence of exotic and native seedlings in a Mediterranean fire-free matorral of central Chile
FIGUEROA,JAVIER A; CAVIERES,LOHENGRIN A;
Revista chilena de historia natural , 2012, DOI: 10.4067/S0716-078X2012000100008
Abstract: we studied the effect of heat shock and wood-fueled smoke on the emergence of native and exotic plant species in soil samples obtained in an evergreen matorral of central chile that has been free of fire for decades. it is located on the eastern foothills of the andes range in san carlos de apoquindo. immediately after collection samples were dried and stored under laboratory conditions. for each two transect, ten samples were randomly chosen, and one of the following treatments was applied: (1) heat-shock treatment, (2) plant-produced smoke treatment, (3) combined heat-and-smoke treatment, and (4) control, corresponding to samples not subjected to treatment. twenty-seven species, representing 13 families, emerged from the soil samples. the most abundant families were asteraceae and poaceae. all of the emerged species were herbaceous, and 18 species were exotic. respect to general hypothesis, there is no evidence for the proposition that fire-free matorral has lower proportion of exotic and native species with fire-related cues than matorral with fires. among the exotic and native, the mean number of species that emerged from soil samples did not change significantly with respect to the control for any of the treatments applied. nevertheless, important species-specific responses were observed. smoke and heat-smoke combination significantly increased the emergence of the exotic species anthriscus caucalis. while smoke-related cues significantly increased the emergence of the exotic species avena barbata, the emergence of the exotic aphanes arvensis and the native bromus berteroanus decreases. for several species our results showed inconsistent responses to fire-related cues compared to those reported in the literature. we suggest that these differences might be related with the fire-history in the populations, an important issue poorly acknowledge in the literature.
Seed germination of species of the Juan Fernández archipiélago under laboratory conditions Germinación de semillas de especies del Archipiélago de Juan Fernández en condiciones de laboratorio
Jaime G Cuevas,Javier A Figueroa
Gayana. Botanica , 2007,
Abstract: The Juan Fernández Islands contain one of the world's most interesting floras. However, their conservation status is fragile due to direct and indirect human activities. With the aim of contributing to the conservation of the native species of these islands, germination trials have been performed under laboratory conditions. We studied the germination patterns and characteristics of 25 taxa of the archipelago, at temperatures between 15°C and 25°C, with 12.5 h. of photoperiod. Thirty-five percent of the studied species germinated immediately (within the first month after sowing), while 50% had a delayed germination. Three species did not germinate. Regarding the germination pattern, nine taxa (53%) germinated synchronously (3 90% of seeds germinated within a month after the first germination), while the remaining 47% germinated asynchronously. Most species showed a high germinative potential (350% of germination). Generally, the germination results were good for most species assayed, with few species requiring special treatments as scarification. For each species, the pre-germinative treatments, germination characteristics and patterns are detailed and discussed in relation to other published antecedents Las Islas Juan Fernández contienen una de las floras más interesantes del mundo. Sin embargo, su estado de conservación es frágil debido a las actividades humanas directas e indirectas. Se realizaron ensayos de germinación bajo condiciones de laboratorio con el propósito de contribuir a la conservación de las especies nativas de las islas. Se estudiaron las características y patrones de germinación de 25 taxa del archipiélago, a temperaturas de entre 15°C y 25°C, con 12,5 h. de fotoperíodo. El treinta y cinco por ciento de las especies germinaron inmediatamente (dentro del primer mes de la siembra), mientras que el 50% de ellas presentaron una germinación retrasada. Tres especies no germinaron. Con respecto al patrón de germinación, nueve especies (53%) germinaron sincrónicamente (3 90% de las semillas germinaron dentro del primer mes después de la primera germinación), por el contrario el 47% germinó asincrónicamente. La mayoría de las especies ensayadas presentaron un alto potencial germinativo (3 50% de germinación). En términos generales, los resultados de germinación fueron buenos para la mayoría de las especies ensayadas, con pocas especies requiriendo tratamientos especiales tales como la escarificación. En el presente estudio se discuten con detalle los tratamientos pre-germinativos, las características y los patrones de germinación para cada un
The effect of heat and smoke on the emergence of exotic and native seedlings in a Mediterranean fire-free matorral of central Chile Efecto del calor y el humo sobre la emergencia de plántulas exóticas y nativas en un matorral mediterráneo libre de fuego en Chile central
JAVIER A FIGUEROA,LOHENGRIN A CAVIERES
Revista chilena de historia natural , 2012,
Abstract: We studied the effect of heat shock and wood-fueled smoke on the emergence of native and exotic plant species in soil samples obtained in an evergreen matorral of central Chile that has been free of fire for decades. It is located on the eastern foothills of the Andes Range in San Carlos de Apoquindo. Immediately after collection samples were dried and stored under laboratory conditions. For each two transect, ten samples were randomly chosen, and one of the following treatments was applied: (1) heat-shock treatment, (2) plant-produced smoke treatment, (3) combined heat-and-smoke treatment, and (4) control, corresponding to samples not subjected to treatment. Twenty-seven species, representing 13 families, emerged from the soil samples. The most abundant families were Asteraceae and Poaceae. All of the emerged species were herbaceous, and 18 species were exotic. Respect to general hypothesis, there is no evidence for the proposition that fire-free matorral has lower proportion of exotic and native species with fire-related cues than matorral with fires. Among the exotic and native, the mean number of species that emerged from soil samples did not change significantly with respect to the control for any of the treatments applied. Nevertheless, important species-specific responses were observed. Smoke and heat-smoke combination significantly increased the emergence of the exotic species Anthriscus caucalis. While smoke-related cues significantly increased the emergence of the exotic species Avena barbata, the emergence of the exotic Aphanes arvensis and the native Bromus berteroanus decreases. For several species our results showed inconsistent responses to fire-related cues compared to those reported in the literature. We suggest that these differences might be related with the fire-history in the populations, an important issue poorly acknowledge in the literature. Nosotros estudiamos el efecto del golpe de calor y del humo de la combustión de material le oso sobre la emergencia de especies de plantas nativas y exóticas en muestras de suelo obtenidas en un matorral siempreverde de Chile central que ha estado libre de fuego por décadas, ubicado en el piedemonte occidental de la Cordillera de los Andes en San Carlos de Apoquindo. Las muestras fueron secadas y almacenadas en condiciones de laboratorio, inmediatamente después de las colectas. En cada uno de los dos transectos, diez muestras fueron aleatoriamente elegidas para la aplicación de los siguientes tratamientos: (1) golpe de calor, (2) humo producido por material vegetal, (3) calor y humo combinado,
Efecto de herbívoros y patógenos en la sobrevivencia y crecimiento de plántulas en un fragmento del bosque templado húmedo de Chiloé, Chile Effect of herbivores and pathogens on the survival and growth of seedlings in a fragment of the Chiloé rainforest, Chile
JAVIER A. FIGUEROA,SERGIO A. CASTRO
Revista chilena de historia natural , 2000,
Abstract: Las plántulas son susceptibles a las condiciones físicas del ambiente, al ataque de patógenos, defoliadores o herbívoros. Los objetivos del estudio fueron determinar el crecimiento y sobrevivencia de las plántulas arbóreas, la proporción de individuos da ados por herbívoros y patógenos, y el efecto de este da o sobre el crecimiento y la sobrevivencia de plántulas del bosque húmedo templado de Chiloé, Chile. La sobrevivencia fue menor en el período de verano y mayor en pleno invierno. Cuando finalizó la fase de monitoreo (11 meses), dos tercios de todas las plántulas sobrevivientes presentaban algún tipo de agresión. Las plántulas con cotiledones presentaban una proporción mayor de plántulas sanas, mientras que aquellas sin cotiledones presentaban una proporción mayor de plántulas agredidas. En Amomyrtus luma los individuos aislados se encontraron preferentemente agredidos. Por el contrario, en las plántulas aisladas de Podocarpus nubigena el número de individuos sanos no difería del número de individuos agredidos. Las plántulas de Amomyrtus luma agrupadas con individuos conespecíficos estaban preferentemente sanas, mientras que la frecuencia de individuos sanos de Amomyrtus luma agrupados con Podocarpus nubigena no difirió significativamente de la frecuencia de individuos agredidos. Las plántulas agrupadas de Podocarpus nubigena estaban todas agredidas. Por otra parte, el vástago de las plántulas creció en promedio aprox. 12 mm en 11 meses. El estado sanitario no afectó significativamente el crecimiento de las plántulas. El 62% de todas las plántulas sobrevivieron 11 meses. El 72% de las plántulas de Podocarpus nubigena sobrevivieron al final del monitoreo, mientras que sobrevivió el 55% de las plántulas de Amomyrtus luma. Sin embargo, no se encontraron diferencias significativas en la sobrevivencia de plántulas entre especies, entre plántulas con y sin cotiledones, y entre plántulas sanas y agredidas, a excepción de las plántulas de Amomyrtus luma cuando no fueron distinguidas por edad. En este último caso sobrevivió una mayor proporción de plántulas agredidas de Amomyrtus luma. Los resultados se discuten en el contexto de las conocidas teorías de defensa de las plantas The physical conditions of the environment, the attack of pathogen microorganisms, defoliating invertebrates and herbivores may affect the growth and survival of woody plant seedlings. Seedling growth, survival, proportion of damaged individuals by herbivores and pathogens, and the effect of these damages on seedling growth and survival were evaluated in this work. Seedling mortality was
Latencia y banco de semillas en plantas de la región mediterránea de Chile central Seed bank and dormancy in plants of the Mediterranean region of central Chile
JAVIER A. FIGUEROA,FABIAN M. JAKSIC
Revista chilena de historia natural , 2004,
Abstract: Los bancos de semillas en las regiones mediterráneas presentan rasgos particulares que los distinguen de bancos de otras regiones del mundo. El banco de semillas es concentración de propágulos viables enterrados en el suelo por períodos variables de tiempo. Los bancos de semillas del matorral de Chile central son principalmente transitorios y funcionalmente semejantes a los bancos presentes en otros ecosistemas mediterráneos no perturbados por fuego, a excepción de Australia. El banco transitorio es aquel formado por semillas que permanecen viables en los horizontes superiores del suelo por no más de 1 a o después de la dispersión. En el matorral de Chile central, en los horizontes superiores del suelo, se encuentra una de las densidades de semillas de hierbas más altas de las regiones mediterráneas. Una gran proporción de esta reserva está constituida por semillas sin latencia, fácilmente germinables, especialmente pastos anuales que germinan en oto o. Con respecto a los mecanismos de latencia de las semillas del banco transitorio responsables del almacenamiento de las semillas en el suelo, nuestra revisión bibliográfica reveló los siguientes principales síndromes de germinación: (1) especies con semillas que deben ser estratificadas en frío debido a la presencia de latencia fisiológica (principalmente hierbas introducidas); (2) especies con semillas que deben ser escarificadas con ácidos o procedimientos mecánicos debido a la presencia de latencia física (principalmente especies le osas nativas); (3) especies con latencia fisiológica que necesitan de estratificación cálida para activar la germinación (hierbas nativas e introducidas). Estos síndromes provocan que la época de germinación en Chile central esté situada entre oto o e inicio de la primavera. Además, no hay referencias sobre la presencia de algún síndrome esporádico de germinación para los componentes de un banco de semillas permanente. Proponemos un modelo estructural y funcional del banco de semillas para el matorral de Chile central, que debería ser enriquecido con futuras investigaciones Seed banks on Mediterranean regions display characteristics that distinguish them from the seed banks of other regions. A seed bank is the concentration of viable propagules buried in the soil for variable periods of time. Seed banks in the Chilean matorral are chiefly transient and functionally similar to seed banks in other Mediterranean ecosystems not disturbed by fire, except for those of Australia. A transient seed bank is that composed of seeds that cannot survive in the upper levels of the soil for
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