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Ciclo anual de la clorofila-α satelital en el archipiélago de Juan Fernández (33°S), Chile Annual cycle of the satellite chlorophyll-a in the Juan Fernandez archipelago (33°S), Chile
Isabel Andrade,Samuel E Hormazabal,Marco A Correa-Ramirez
Latin american journal of aquatic research , 2012,
Abstract: La variabilidad espacial y temporal del ciclo anual de la clorofila-α en el archipiélago de Juan Fernández se analiza usando ocho anos de datos satelitales de clorofila-α, viento, corrientes y nivel del mar. Este archipiélago está conformado por tres islas: Robinson Crusoe-Santa Clara (RC-SC) y Alejandro Selkirk (AS). Las islas RC-SC se encuentran en una región de alta energía cinética y mayores concentraciones de clorofila-α definida como Zona de Transición Costera, en cambio la isla AS se encuentra en una región de baja energía cinética y menores concentraciones de clorofila-α denominada Zona Oceánica. RC-SC posee un incremento de las concentraciones de clorofila-a en el lado suroeste, mientras que AS posee sus mayores concentraciones en el lado oeste, indicando la presencia de procesos forzantes diferentes. En ambas islas el ciclo anual de la clorofila es significativo y comienza a incrementar en abril, alcanzando valores relativamente altos entre junio y noviembre, disminuyendo hacia diciembre, hasta alcanzar un mínimo hacia fines de marzo. Este ciclo anual aparece desacoplado con el viento y acoplado con la energía cinética. Incrementos invernales de clorofila-a aparecen vinculados con remolinos de mesoescala provenientes de la zona continental, mientras que incrementos primaverales se podrían asociar a procesos locales vinculados al "efecto masa de isla". En ambas islas existen incrementos significativos de la clorofila-a en la banda anual y cuasi-bianual, pero sólo en AS se encontró una fluctuación significativa en la banda interanual vinculada con el Nino y la Oscilación del Sur. The spatial and temporal variability of the annual cycle of chlorophyll-a in the Juan Fernandez archipelago is analyzed through eight years of satellite data of chlorophyll-a, wind, currents and sea level. This archipelago consists of three islands: Robinson Crusoe-Santa Clara (RC-SC) and Alexander Selkirk (AS). The RC-SC islands are in a region of high eddy kinetic energy and higher concentrations of chlorophyll-a, defined as Coastal Transition Zone, whereas the AS island is in a region with low eddy kinetic energy and lower concentrations of chlorophyll-a called Oceanic Zone. RC-SC has an increase in chlorophyll-a concentrations on the southwest side, while AS has its highest concentrations on the west side, indicating the presence of different forcing. On both islands the annual cycle of chlorophyll is significant and begins to increase in April, reaching relatively high values between June and November, decreasing to its lowest values in December, reaching a minimum
Efeito do Sombreamento sobre o Teor de Clorofila e Crescimento Inicial do Jequitibá-rosa Effect of Shadeness Over Chlorophyll Level and Initial Growth of Cariniana legalis
Gizelda Maia Rego,Edilberto Possamai
Pesquisa Florestal Brasileira , 2011, DOI: 10.4336/2012.pfb.53.179
Abstract: Com o objetivo de avaliar os efeitos de períodos de sombreamento sobre o crescimento inicial e concentra es de clorofila em mudas de jequitibá- rosa (Cariniana legalis), foi instalado um experimento no viveiro de pesquisa da Embrapa Florestas, em Colombo, PR. O delineamento experimental foi o de blocos ao acaso, com cinco tratamentos e quatro repeti es. Os tratamentos estabelecidos foram: 100 % (pleno sol); 70 %; 64 %, 44 % e 34 % de radia o solar incidente. A altura e diametro do coleto foram monitorados em intervalos de 30 dias, dos 60 aos 180 dias após a emergência (DAE). O peso da matéria seca total, aérea e radicial, área foliar, clorofila a e b e clorofila total, foram medidos aos 180 DAE. O percentual de 63,07 % de RFA (radia o fotossinteticamente ativa) proporcionou o maior crescimento em altura das mudas. As maiores médias de diametro do coleto ocorreram com as mudas submetidas a pleno sol. O oposto foi observado com a área foliar, onde observaram-se as maiores médias quando as mudas foram submetidas ao maior percentual de sombreamento (34 % de luminosidade). O acúmulo de matéria seca total foi estimado para 54,40 % de RFA. Os teores de clorofila a e b foram maiores nas folhas das mudas sombreadas. Concluiu-se que mudas do jequitibá-rosa, em sua fase inicial, apresentam bom crescimento quando cultivadas na faixa de 54 % a 64 % de luminosidade. Toevaluate the effects of periods of shadeness over the initial growth and concentrations of chlorophyll in Cariniana legalis (Mart.) Kuntze seedlings, an experiment was installed in the research nursery of Embrapa Florestas, at Colombo/PR, Brazil. It was utilized randomized blocks design with five treatments and four replications. The treatments established were: 100% (entire light); 70%, 64%, 44% and 34% of sun radiation. Monitoring of height and diameter were made under intervals of 30 days, from 60o to 180o day after emergency (DAE). Air total dry matter weight of roots, leaf area, chlorophyll a, chlorophyll b and total chlorophyll were measured 180 days after emergency. FAR (Photosynthetic Active Radiation) of 63, 07% led to the best seedling growth in height. Best diameter averages of the region that divides roots from stem occurred with seedlings submitted to entire light. The contrary was observed with leaf area, where major averages were observed when seedlings were submitted to shadeness (34% of light). Dry matter estimates accumulated on 54,40 % of FAR. Chlorophyll a and b levels were higher in the leaves of seedlings cultivated in shadow. Seedlings of Cariniana legalis, at the first phas
EVALUACIóN DE UN INSTRUMENTO MEDIDOR DE CLOROFILA EN LA DETERMINACIóN DE NIVELES DE NITRóGENO FOLIAR EN MAíZ Evaluation of a chlorophyll meter on the assessment of foliar nitrogen in corn  [cached]
Rafael Novoa S.-A.,Nicolás Villagrán A.
Agricultura Técnica , 2002,
Abstract: Con el objetivo de evaluar el uso de un instrumento medidor de clorofila (SPAD 502) como un indicador del contenido de N en hojas de maíz (Zea mays), se estableció un ensayo de campo en el Instituto de Investigaciones Agropecuarias, Centro Regional de Investigación La Platina, Santiago, Chile. Se aplicaron cuatro tratamientos de fertilización nitrogenada usando urea, 0, 100, 200 y 400 kg de N ha-1, con cuatro repeticiones, dispuestas en bloques al azar. La mitad de la dosis se aplicó a la siembra y el resto se aplicó al estado de 6-7 hojas. Se muestrearon las hojas más recientemente maduras del maíz en cada tratamiento. A éstas se les determinaron los niveles de clorofila con el SPAD. Se hicieron diez mediciones por hoja, en el limbo, 5 a cada lado de la vena central, en 3 plantas por tratamiento. A esas mismas hojas se les midió el contenido de N en laboratorio. Las mediciones se hicieron en dos épocas, cuando el maíz tenía 5 a 6 hojas y poco después de la floración. De acuerdo a los resultados obtenidos, las mediciones de clorofila realizadas con el SPAD 502 y el análisis de porcentaje de N están altamente correlacionados. En la primera y segunda fecha se obtuvo un r2 de 0,88 y 0,81, respectivamente. En este caso y para la primera época, valores del SPAD inferiores a 35,3, equivalentes a un contenido de 1,84% de N en las hojas, estarían indicando que es necesario aplicar N. In order to evaluate the use of a chlorophyll meter (SPAD 502), as a tool to estimate the N content of corn (Zea mays) leaves, a field experiment of corn hybrid ‘INIA 160’ was sown at National Agricultural Research Institute (INIA), La Platina Experimental Station, Santiago, Chile. Four nitrogen treatments (0, 100, 200, 400 kg N ha-1) using urea were applied in a completely randomized block design with four replicates. Half of the N was applied at sowing and half at the 6-7 leaf growth stage. The most recently mature leaves were sampled for each treatment. The chlorophyll levels of leaves were measured with the SPAD. Ten measurements were made per leaf: 5 on each side of the central vein for 3 plants per treatment. These same leaves were taken to the lab for N chemical analysis. Readings were taken at two stages, when the corn had 5-6 leaves and a few days after full tassel. According to the results, the SPAD chlorophyll meter readings and foliar N percentage content were highly correlated. At the first and second reading dates, r2 was 0.88 and 0.81, respectively. In this case at the six-leaf stage, SPAD values of less than 35.3, equivalent to 1.84% N in the leaves, would indicate
Revisiting chlorophyll data along the coast in north-central Chile, considering multiscale environmental variability Reinterpretando datos de clorofila en la costa centro-norte de Chile, considerando variabilidad ambiental de multiescala  [cached]
VIVIAN MONTECINO,M. ALEJANDRA PAREDES,PEDRO PAOLINI,JOSé RUTLLANT
Revista chilena de historia natural , 2006,
Abstract: Phytoplankton abundance in the surface mixed layer of the coastal ocean responds to environmental changes at various time scales. Here the "warm", "cold" and "neutral" phases of "three environmental cycles" have been jointly considered to assess chlorophyll-a (Chl-a) biomass variability for both the active and relaxed phases of the local, wind-driven coastal upwelling: (i) the interannual ENSO cycle (ii) the annual (seasonal) cycle and (iii) the intraseasonal cycle associated with equatorially-sourced, ocean trapped-waves along the coast in northern Chile. The main goal of this study is to quantitatively assess the variability of the depth- integrated Chl-a biomass in the euphotic zone ( Chl-a) in terms of an overall "environmental condition" over a 50 km upwelling sensitive coastal strip, revisiting published and unpublished Chl-a ship (Cship = Chl-a + Phaeopigments) data. All possible "environmental conditions" combinations were further ranked into seven "environmental indices" ranging from 0 ("absolutely cold") to 6 ("absolutely warm"). Out of 332 samples of Chl-a, 198/134 were obtained during active/relaxed upwelling conditions from which 24/38 and 30/36 samples were associated with the simultaneous occurrence of at least two "cold"/"warm" phases of the three environmental cycles ("cold"/"warm" environmental conditions), respectively. Lower Chl-a values during "cold" and "warm" environmental conditions relative to the "neutral" ones reached statistical significance for both active and relaxed conditions (144/60 samples respectively). Higher turbulent mixing during "cold" environmental conditions and a deeper nutricline during "warm" ones would explain lower Chl-a-values. Satellite chlorophyll (Csat) data obtained in clear skies (active upwelling only), showed a similar distribution to those of Chl-a when classified into the corresponding "environmental indices". These results suggest that during "neutral" (transitional) "environmental conditions", nutrient supply, mean light exposure and mixing thresholds, including biological interactions, could be more effective in producing a higher phytoplankton biomass, in spite of a larger dispersion La abundancia de fitoplancton en la capa de mezcla superficial del océano costero responde a cambios ambientales en diferentes escalas de tiempo. Aquí se han considerado conjuntamente las fases "cálida", "fría" y "neutra" de "tres ciclos ambientales" para estimar la variabilidad de la biomasa de la clorofila (Chl-a) para las fases activa y relajada de la surgencia costera inducida por el viento local: (i) el ci
Macronutrient uptake and carotenoid/chlorophyll a ratio in the dinoflagellate Amphidinium carteri Hulburt, cultured under different nutrient and light conditions Consumo de macronutrientes y proporción de carotenoides/clorofila a en el dinoflagelado Amphidinium carteri Hulburt, cultivado bajo diferentes condiciones de luz y nutrientes  [cached]
Enrique Valenzuela-Espinoza,Roberto Millán-Nú?ez,Eduardo Santamaría-del-ángel,Charles C. Trees
Hidrobiológica , 2011,
Abstract: Population growth, macronutrient (,) uptake and carotenoids/chlorophyll a ratio we determined in Amphidinium carteri Hulburt, cultured under conditions of continuous light (50, 150, 300 and 750 μmol quanta m-2 s-1) and three nutrient concentrations NaNO3/NaH2PO4 at 441.5/18.1 μM (low) 883/36.3 μM (medium) and 1766/72.6 μM (high). Both nutrient and irradiance had a significant effect (p < 0.05) on cellular abundance during the period of culture, except for the fourth and seventh day for nutrients (p > 0.05). In cultures under low nutrient condition, NO- and PO4- were almost depleted by the fifth day and in cultures with medium nutrient this condition occurred in the sixth day; whereas, at high nutrient condition the nutrients were not depleted. We concluded that A. carteri had higher growth rates and nutrient consumption at 300 μmol quanta m-2 s-1 during the first five days and in general the effect of nutrients on the pigment ratios was not significant (p > 0.05). However, the average peridinin/Chla ratio decreased up to 72% from the lowest and the highest irradiance. The opposite was observed for the average of diadinoxanthin/Chla ratio that increased almost two-fold, and the averages dinoxanthin and diatoxanthin to Chla ratios that increased from low to high irradiances. The average diatoxanthin/Chla ratio at 750 μmol quanta m-2 s-1 increased up to 2.7-fold from the exponential to the stationary phase only in the low and medium nutrient concentration. Likewise, the average peridinin, dinoxanthin and diatoxanthin to Chla ratios were not significantly different at 50 and 150 μmol quanta m-2 s-1. These results indicate important changes in average carotenoids/Chla ratios in A. carteri cultured under different irradiances. Se evaluaron el crecimiento poblacional, consumo de macronutrientes (,) y proporción de carotenoides/clorofila a en Amphidinium carteri Hulburt, cultivado durante 7 días, bajo condiciones de luz continua: 50, 150, 300 y 750 μmol quanta m-2 s-1 y tres concentraciones de nutrientes NaNO3/NaH2PO4 (441.5/18.1 μM (bajo); 883/36.3 μM (medio) y 1766/72.6 μM (alto). La abundancia celular fue significativamente afectada (p < 0.05) tanto por el nivel de nutrientes como por la irradianza durante el periodo de cultivo, excepto para el nivel de nutriente en el cuarto y séptimo día. En los cultivos con bajo nutriente, el se agotaron casi totalmente al quinto día, y en cultivos con medio nutriente ocurrió al sexto día; mientras que en alta concentración de nutrientes, éstos no se agotaron. Se concluye que A. carteri tuvo la mayor tasa de crecimiento y
Determination of nitrogen and chlorophyll levels in bean-plant leaves by using spectral vegetation bands and indices Discrimina o de teores de nitrogênio e clorofila foliares do feijoeiro por meio de bandas e índices de vegeta o espectrais
Selma Alves Abrah?o,Francisco de Assis de Carvalho Pinto,Daniel Mar?al de Queiroz,Nerilson Terra Santos
Revista Ciência Agron?mica , 2013,
Abstract: This study aimed to develop classifiers based on different combinations of spectral bands and vegetation indices from original, segmented and reflectance images in order to determine the levels of leaf nitrogen and chlorophyll in the bean, and to define the best time and best variables. A remote-sensing system was used, consisting of a helium balloon and two small-format digital cameras. Besides the individual spectral bands, four vegetation indices were tested: simple ratio, normalized difference, normalized difference in the green band, and modified-chlorophyll absorption. The classifiers proved to be efficient in determining levels of leaf nitrogen and chlorophyll. The best time for determining leaf N content was at 13 DAE (stage V4). The best classifiers for that time used as input variables two indices from segmented reflectance images, one index related to the canopy structure and the other related to chlorophyll, with a Kappa ranging from 0.26 to 0.31. The best time to discriminate leaf chlorophyll content was 21 DAE (stage V4). The best classifier used as input variables two original images, one in the red band and one in the blue with a Kappa of 0.47. Objetivou-se desenvolver classificadores com base em diferentes combina es de bandas e índices de vegeta o espectrais de imagens originais, segmentadas e reflectancias, para discrimina o de teores de nitrogênio e clorofila foliares do feijoeiro, definindo a melhor época e as melhores variáveis. Foi utilizado um sistema de sensoriamento remoto constituído por um bal o a gás hélio e duas cameras digitais de pequeno formato. Além das bandas isoladamente, foram testados quatro índices de vegeta o: da raz o simples, da diferen a normalizada, da diferen a normalizada utilizando a banda do verde e o da absor o de clorofila modificado. Os classificadores demonstraram serem eficientes na discrimina o de teores de nitrogênio e clorofila foliares. A melhor época para discriminar teor de nitrogênio foliar foi aos 13 DAE (estádio V4). Os melhores classificadores para esta época utilizaram como entrada dois índices em imagens reflectancia segmentada, um índice relacionado com a estrutura do dossel e outro relacionado com a clorofila, com Kappa variando entre 0,26 a 0,31. Para discriminar teor de clorofila foliar, a melhor época foi aos 21 DAE (estádio V4). O melhor classificador utilizou como entrada duas imagens originais, uma da banda vermelha e outra da banda azul, com Kappa de 0,47.
Assessment of catalase activity, lipid peroxidation, chlorophyll-a, and growth rate in the freshwater green algae Pseudokirchneriella subcapitata exposed to copper and zinc Evaluación de la actividad de la catalasa, peroxidación lipídica, clorofila-a y tasa de crecimiento en la alga verde de agua dulce Pseudokirchneriella subcapitata expuesta a cobre y zinc
Paulina Soto,Hernán Gaete,María Eliana Hidalgo
Latin american journal of aquatic research , 2011,
Abstract: In this work, the effect of copper and zinc on green alga Pseudokirchneriella subcapitata was evaluated through catalase activity, lipid peroxidation by TBARS essay, growth rate, and the chlorophyll-a concentration. Catalase activity increased significantly (P < 0.05) in comparison to the control at 0.1 mg L-1 copper and 0.075 mg L-1 zinc, whereas the damage to the cell membrane expressed as nmols/10(6)cell of malondialdehyde increased significantly (P < 0.05) at 0.025 mg L-1 copper and 0.1 mg L-1 zinc. On the other hand, a significant (P < 0.05) decrease in chlorophyll-a concentration was found at 0.075 mg L-1 of both metals. The results showed that catalase activity, lipid peroxidation, and chlorophyll-a concentration were more sensitive to metals than the growth rate. En este trabajo, se evaluó el efecto del cobre y zinc en la alga verde Pseudokirchneriella subcapitata a través de la actividad catalasa, peroxidación lipídica por el ensayo TBARS, tasa de crecimiento y concentración de clorofila-a. La actividad catalasa aumentó significativamente (P < 0,05) en comparación al control en 0,1 mg L-1 y 0,075 mg L-1 de cobre y zinc respectivamente, mientras que el da o en la membrana celular expresado en nanomols/10(6) células de malondialdehído aumentó significativamente en 0,025 mg L-1 y 0,1 mg L-1 de cobre y zinc respectivamente. Por otra parte, hubo una disminución significativa (P < 0,05) en la concentración de clorofila-a en ambos metales a 0,075 mgL-1. Los resultados mostrados en actividad catalasa, peroxidación lipídica y concentración de clorofila-a son parámetros más sensibles que la tasa de crecimiento a los metales.
Variabilidad interanual de clorofila en el golfo de California  [cached]
T. Leticia Espinosa-Carreón,J. Eduardo Valdez-Holguín
Ecología Aplicada , 2007,
Abstract: El Golfo de California es caracterizado como un mar semicerrado y una cuenca de evaporación. Se ha divido en varias zonas físicas y biogeográficas, características dadas por la dinámica de cada zona. El objetivo de este trabajo fue el de conocer la variabilidad interanual de la clorofila de Septiembre de 1997 a Diciembre de 2002 bajo condiciones El Ni o y La Ni a. Se obtuvieron del sensor SeaWiFS los compuestos semanales de clorofila con resolución de 9 km por píxel, para el periodo de estudio. Los resultados más sobresalientes de la distribución promedio de clorofila sugiere que el Golfo de California puede dividirse en tres zonas: oligotrófica (boca del golfo), mesotrófica (parte central) y eutrófica (región costera y parte norte del golfo, incluida la región de las Grandes Islas). La estacionalidad de la clorofila indica la predominancia de la se al anual. Es evidente la variabilidad interanual producida por los eventos El Ni o 1997-1998 y por La Ni a 1998-2001. El efecto de El Ni o 1997-1998 es fuerte sobre la distribución de clorofila, el cambio hacia condiciones frías de La Ni a durante 1998-1999 se refleja en anomalías negativas de biomasa fitoplanctónica, pero en positivas en los a os 2000 y 2001
COMPARACIóN DE LA ESTIMACIóN DE LA CLOROFILA-a MEDIANTE LOS MéTODOS ESPECTROFOTOMéTRICO Y FLUOROMéTRICO
RIVERA R.,CARLOS; ZAPATA A.,áNGELA; PINILLA,GABRIEL; DONATO,JHON; CHAPARRO,BEATRIZ; JIMéNEZ,PAOLA;
Acta Biológica Colombiana , 2005,
Abstract: in four mountain aquatic ecosystems of altiplano cundiboyacense, colombia, we compared through analysis regression data set of chlorophyll-a obtained with spectorophotometric (tricromatic formula) and fluorometric (welschmeyer) methods. the analysis showed that the spectrophotometric method overestimated the chlorophyll-a concentration, but it could be used with precaution in the lower trophic environments. an equation that relates the two chlorophyll-a measures was obtained.
Fluorescência da clorofila-a e varia o da simetria como ferramentas de investiga o de plantas sob estresse Chlorophyll-a fluorescence and symmetry deviation as tools for investigating plants under stress
Paulo Eduardo de Menezes Silva,Etenaldo Felipe Santiago,Eder Marques da Silva,Yzel Rondon Súarez
IDESIA , 2011,
Abstract: Perturba es microambientais em diferentes sistemas e indivíduos podem resultar numa tendência para a assimetria flutuante, que consiste no desvio n o direcional da simetria de uma estrutura bilateral normalmente distribuída numa popula o. Neste sentido, indivíduos incapazes de exibirem respostas plásticas aos distúrbios do desenvolvimento acontecidos ao acaso, seja de origem genética ou ambiental, podem exibir pequenos desvios de simetria em órg os com estrutura bilateral, como as folhas. Dessa forma, analisar a escala morfológica de plantas via padr o de simetria das folhas, vem se tornando uma ferramenta eficaz para descrever a estabilidade do desenvolvimento de plantas sob condi es de estresse. Assim, este estudo objetivou analisar o padr o de simetria bem como a fluorescência da clorofila-a em folíolos de Glycine max (L.) Merrill. (var. BRS 239) submetidos ao estresse por radia o ultravioleta. Determinou-se os desvios de simetria (ds), o comprimento médio (CML) e a largura máxima do limbo (LML) assim como os parametros de fluorescência da clorofila-a em folíolos de plantas jovens de G. max submetidas a 0, 30, 60, 120 ou 240 minutos semanais de radia o ultravioleta-C (UV-C) durante quatro semanas, submetendo os valores à análise de variancia e ao teste de Tukey (p<0.05). Os resultados demonstraram redu es significativas em CML e LML, aumento significativo no ds nos folíolos irradiados, bem como queda no rendimento quantico potencial do fotossistema II (Fv/Fm) e no índice de performance (IP). As análises de simetria foliar demonstraram alta correla o com o nível de estresse aos quais as plantas foram submetidas, sendo uma importante análise para averiguar o fitness da planta por se tratar de uma metodologia n o-invasiva e de fácil manipula o. Environmental disturbances in various systems and individuals can result in a tendency for fluctuating asymmetry, which consists of a non-directional deviation from symmetry of a bilateral structure in a normally distributed population. Individuals unable to exhibit plastic responses to developmental disorders that occur at random, either genetic or environmental, may exhibit slight deviations from symmetry in organs with bilateral structure such as leaves. Thus analyzing plants by the morphological pattern of symmetry of the leaves has become an effective tool to describe the developmental of plants under stress conditions. This study aimed to analyze if the pattern of symmetry can be used as a tool to investigate the stress level to which a plant is subjected, using ultraviolet-C radiation (UV-C) as sou
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