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Outdoor allergens.

Burge, H A; Rogers, C A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/2000 Português
Relevância na Pesquisa
28.15565%
Outdoor allergens are an important part of the exposures that lead to allergic disease. Understanding the role of outdoor allergens requires a knowledge of the nature of outdoor allergen-bearing particles, the distributions of their source, and the nature of the aerosols (particle types, sizes, dynamics of concentrations). Primary sources for outdoor allergens include vascular plants (pollen, fern spores, soy dust), and fungi (spores, hyphae). Nonvascular plants, algae, and arthropods contribute small numbers of allergen-bearing particles. Particles are released from sources into the air by wind, rain, mechanical disturbance, or active discharge mechanisms. Once airborne, they follow the physical laws that apply to all airborne particles. Although some outdoor allergens penetrate indoor spaces, exposure occurs mostly outdoors. Even short-term peak outdoor exposures can be important in eliciting acute symptoms. Monitoring of airborne biological particles is usually by particle impaction and microscopic examination. Centrally located monitoring stations give regional-scale measurements for aeroallergen levels. Evidence for the role of outdoor allergens in allergic rhinitis is strong and is rapidly increasing for a role in asthma. Pollen and fungal spore exposures have both been implicated in acute exacerbations of asthma...

Outdoor air pollution and lung cancer.

Cohen, A J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/2000 Português
Relevância na Pesquisa
27.666208%
In the 1950s evidence of an ongoing epidemic of lung cancer in the United States and Western Europe led researchers to examine the role of outdoor air pollution, which was considered by some to be a likely cause. Although epidemiologic research quickly identified the central role of cigarette smoking in this epidemic, and despite progress in reducing outdoor air pollution in Western industrialized countries, concerns that ambient air pollution is causing lung cancer have persisted to the present day. This concern is based on the fact that known carcinogens continue to be released into outdoor air from industrial sources, power plants, and motor vehicles, and on a body of epidemiologic research that provides some evidence for an association between outdoor air pollution and lung cancer. This article reviews the epidemiologic evidence for this association and discusses the limitations of current studies for estimating the lung cancer risk in the general population. It also identifies research needs and suggests possible approaches to addressing outstanding questions.

Effects of bioaerosol polluted outdoor air on airways of residents: a cross sectional study

Herr, C; zur Nieden, A; Jankofsky, M; Stilianakis, N; Boedeker, R; Eikmann, T
Fonte: BMJ Group Publicador: BMJ Group
Tipo: Artigo de Revista Científica
Publicado em /05/2003 Português
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27.219314%
Background: Bioaerosol pollution of workplace and home environments mainly affects airways and mucous membranes. The effect of environmental outdoor residential bioaerosol pollution, for example, livestock holdings, farming, and waste disposal plants, is unclear.

Olfactory Attraction of the Larval Parasitoid, Hyposoter horticola, to Plants Infested with Eggs of the Host Butterfly, Melitaea cinxia

Castelo, Marcela K.; van Nouhuys, Saskya; Corley, Juan C.
Fonte: University of Wisconsin Library Publicador: University of Wisconsin Library
Tipo: Artigo de Revista Científica
Publicado em 04/06/2010 Português
Relevância na Pesquisa
27.188079%
Parasitoids locate inconspicuous hosts in a heterogeneous habitat using plant volatiles, some of which are induced by the hosts. Hyposoter horticola Gravenhost (Hymenoptera: Ichneumonidae) is a parasitoid of the Glanville fritillary butterfly Melitaea cinxia L. (Lepidoptera: Nymphalidae). Melitaea cinxia lays eggs in clusters on leaves of Plantago lanceolata L. (Lamiales: Plantaginaceae) and Veronica spicata L. (Lamiales: Plantaginaceae). The parasitoid oviposits into host larvae that have not yet hatched from the egg. Thus, though H. horticola is a parasitoid of Melitaea cinxia larvae, it must find host eggs on plants that have not been fed on by the larvae. Using a Y-tube olfactometer, the response of H. horticola to odors of Melitaea cinxia and extracts of the attacked plant species were tested. Three week-old eggs (near hatching) were attractive to young H. horticola, but one week-old eggs were attractive only to old or experienced H. horticola. Melitaea cinxia larvae were not attractive. A water extract of P. lanceolata was attractive, but ethanol or hexane extracts were not. None of the extracts of V. spicata were attractive. Leaves of V. spicata were attractive only if harboring eggs, but P. lanceolata leaves with eggs were not. Free flying H. horticola in a large outdoor enclosure were presented with host and plant cues. As in the olfactometer...

Piriformospora indica mycorrhization increases grain yield by accelerating early development of barley plants

Achatz, Beate; Kogel, Karl-Heinz; Franken, Philipp; Waller, Frank
Fonte: Landes Bioscience Publicador: Landes Bioscience
Tipo: Artigo de Revista Científica
Português
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Root colonization by the basidiomycete fungus Piriformospora indica induces host plant tolerance against abiotic and biotic stress, and enhances growth and yield. As P. indica has a broad host range, it has been established as a model system to study beneficial plant-microbe interactions. Moreover, its properties led to the assumption that P. indica shows potential for application in crop plant production. Therefore, possible mechanisms of P. indica improving host plant yield were tested in outdoor experiments: Induction of higher grain yield in barley was independent of elevated pathogen levels and independent of different phosphate fertilization levels. In contrast to the arbuscular mycorrhiza fungus Glomus mosseae total phosphate contents of host plant roots and shoots were not significantly affected by P. indica. Analysis of plant development and yield parameters indicated that positive effects of P. indica on grain yield are due to accelerated growth of barley plants early in development.

Sources of Bacteria in Outdoor Air across Cities in the Midwestern United States ▿ †

Bowers, Robert M.; Sullivan, Amy P.; Costello, Elizabeth K.; Collett, Jeff L.; Knight, Rob; Fierer, Noah
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /09/2011 Português
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Bacteria are abundant in the atmosphere, where they often represent a major portion of the organic aerosols. Potential pathogens of plants and livestock are commonly dispersed through the atmosphere, and airborne bacteria can have important effects on human health as pathogens or triggers of allergic asthma and seasonal allergies. Despite their importance, the diversity and biogeography of airborne microorganisms remain poorly understood. We used high-throughput pyrosequencing to analyze bacterial communities present in the aerosol fraction containing fine particulate matter of ≤2.5 μm from 96 near-surface atmospheric samples collected from cities throughout the midwestern United States and found that the communities are surprisingly diverse and strongly affected by the season. We also directly compared the airborne communities to those found in hundreds of samples representing potential source environments. We show that, in addition to the more predictable sources (soils and leaf surfaces), fecal material, most likely dog feces, often represents an unexpected source of bacteria in the atmosphere at more urbanized locations during the winter. Airborne bacteria are clearly an important, but understudied, component of air quality that needs to be better integrated into efforts to measure and model pollutants in the atmosphere.

Robust Crop and Weed Segmentation under Uncontrolled Outdoor Illumination

Jeon, Hong Y.; Tian, Lei F.; Zhu, Heping
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 10/06/2011 Português
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28.23288%
An image processing algorithm for detecting individual weeds was developed and evaluated. Weed detection processes included were normalized excessive green conversion, statistical threshold value estimation, adaptive image segmentation, median filter, morphological feature calculation and Artificial Neural Network (ANN). The developed algorithm was validated for its ability to identify and detect weeds and crop plants under uncontrolled outdoor illuminations. A machine vision implementing field robot captured field images under outdoor illuminations and the image processing algorithm automatically processed them without manual adjustment. The errors of the algorithm, when processing 666 field images, ranged from 2.1 to 2.9%. The ANN correctly detected 72.6% of crop plants from the identified plants, and considered the rest as weeds. However, the ANN identification rates for crop plants were improved up to 95.1% by addressing the error sources in the algorithm. The developed weed detection and image processing algorithm provides a novel method to identify plants against soil background under the uncontrolled outdoor illuminations, and to differentiate weeds from crop plants. Thus, the proposed new machine vision and processing algorithm may be useful for outdoor applications including plant specific direct applications (PSDA).

Arsenic(V) Removal in Wetland Filters Treating Drinking Water with Different Substrates and Plants

Wu, Min; Li, Qingyun; Tang, Xianqiang; Huang, Zhuo; Lin, Li; Scholz, Miklas
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica
Português
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Constructed wetlands are an attractive choice for removing arsenic (As) within water resources used for drinking water production. The role of substrate and vegetation in As removal processes is still poorly understood. In this study, gravel, zeolite (microporous aluminosilicate mineral), ceramsite (lightweight expanded clay aggregate) and manganese sand were tested as prospective substrates while aquatic Juncus effuses (Soft Rush or Common Rush) and terrestrial Pteris vittata L. (Chinese Ladder Brake; known as As hyperaccumulator) were tested as potential wetland plants. Indoor batch adsorption experiments combined with outdoor column experiments were conducted to assess the As removal performances and process mechanisms. Batch adsorption results indicated that manganese sand had the maximum As(V) adsorption rate of 4.55 h–1 and an adsorption capacity of 42.37 μg/g compared to the other three aggregates. The adsorption process followed the pseudo-first-order kinetic model and Freundlich isotherm equations better than other kinetic and isotherm models. Film-diffusion was the rate-limiting step. Mean adsorption energy calculation results indicated that chemical forces, particle diffusion and physical processes dominated As adsorption to manganese sand...

MYB and bHLH transcription factor transgenes increase anthocyanin pigmentation in petunia and lisianthus plants, and the petunia phenotypes are strongly enhanced under field conditions

Schwinn, Kathy E.; Boase, Murray R.; Bradley, J. Marie; Lewis, David H.; Deroles, Simon C.; Martin, Cathie R.; Davies, Kevin M.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 05/11/2014 Português
Relevância na Pesquisa
27.42038%
Petunia line Mitchell [MP, Petunia axillaris × (P. axillaris × P. hybrida)] and Eustoma grandiflorum (lisianthus) plants were produced containing a transgene for over-expression of the R2R3-MYB transcription factor [TF; ROSEA1 (ROS1)] that up-regulates flavonoid biosynthesis in Antirrhinum majus. The petunia lines were also crossed with previously produced MP lines containing a Zea mays flavonoid-related basic helix-loop-helix TF transgene (LEAF COLOR, LC), which induces strong vegetative pigmentation when these 35S:LC plants are exposed to high-light levels. 35S:ROS1 lisianthus transgenics had limited changes in anthocyanin pigmentation, specifically, precocious pigmentation of flower petals and increased pigmentation of sepals. RNA transcript levels for two anthocyanin biosynthetic genes, chalcone synthase and anthocyanidin synthase, were increased in the 35S:ROS1 lisianthus petals compared to those of control lines. With MP, the 35S:ROS1 calli showed novel red pigmentation in culture, but this was generally not seen in tissue culture plantlets regenerated from the calli or young plants transferred to soil in the greenhouse. Anthocyanin pigmentation was enhanced in the stems of mature 35S:ROS1 MP plants, but the MP white-flower phenotype was not complemented. Progeny from a 35S:ROS1 × 35S:LC cross had novel pigmentation phenotypes that were not present in either parental line or MP. In particular...

Automated Mobile System for Accurate Outdoor Tree Crop Enumeration Using an Uncalibrated Camera

Nguyen, Thuy Tuong; Slaughter, David C.; Hanson, Bradley D.; Barber, Andrew; Freitas, Amy; Robles, Daniel; Whelan, Erin
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 28/07/2015 Português
Relevância na Pesquisa
27.694219%
This paper demonstrates an automated computer vision system for outdoor tree crop enumeration in a seedling nursery. The complete system incorporates both hardware components (including an embedded microcontroller, an odometry encoder, and an uncalibrated digital color camera) and software algorithms (including microcontroller algorithms and the proposed algorithm for tree crop enumeration) required to obtain robust performance in a natural outdoor environment. The enumeration system uses a three-step image analysis process based upon: (1) an orthographic plant projection method integrating a perspective transform with automatic parameter estimation; (2) a plant counting method based on projection histograms; and (3) a double-counting avoidance method based on a homography transform. Experimental results demonstrate the ability to count large numbers of plants automatically with no human effort. Results show that, for tree seedlings having a height up to 40 cm and a within-row tree spacing of approximately 10 cm, the algorithms successfully estimated the number of plants with an average accuracy of 95.2% for trees within a single image and 98% for counting of the whole plant population in a large sequence of images.

Outdoor Allergens

Rogers, Christine Anne; Burge, Harriet A.
Fonte: The National Institute of Environmental Health Sciences Publicador: The National Institute of Environmental Health Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
28.15565%
Outdoor allergens are an important part of the exposures that lead to allergic disease. Understanding the role of outdoor allergens requires a knowledge of the nature of outdoor allergen-bearing particles, the distributions of their source, and the nature of the aerosols (particle types, sizes, dynamics of concentrations). Primary sources for outdoor allergens include vascular plants (pollen, fern spores, soy dust), and fungi (spores, hyphae). Nonvascular plants, algae, and arthropods contribute small numbers of allergen-bearing particles. Particles are released from sources into the air by wind, rain, mechanical disturbance, or active discharge mechanisms. Once airborne, they follow the physical laws that apply to all airborne particles. Although some outdoor allergens penetrate indoor spaces, exposure occurs mostly outdoors. Even short-term peak outdoor exposures can be important in eliciting acute symptoms. Monitoring of airborne biological particles is usually by particle impaction and microscopic examination. Centrally located monitoring stations give regional-scale measurements for aeroallergen levels. Evidence for the role of outdoor allergens in allergic rhinitis is strong and is rapidly increasing for a role in asthma. Pollen and fungal spore exposures have both been implicated in acute exacerbations of asthma...

Desenho urbano climaticamente orientado: a influência da vegetação no ambiente térmico externo

Minella, Flávia Cristina Osaku
Fonte: Curitiba Publicador: Curitiba
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
27.054507%
Vegetation can produce measurable positive effects on the thermal field of urban spaces. In view of thermal inadequacies in outdoor spaces, there is a need for projects and urban plans which consider the use of vegetation as strategic element for the creation of thermal comfort conditions in open spaces. In this sense, the relevance of this study is the proposition of an index which estimates the amount of vegetation fraction needed to reduce the air temperature in urban environments. The index was developed for the city of Curitiba, specifically for its central arteries such as Avenida Sete de Setembro and Avenida Linha Verde. Additionally, pilot studies for the cities of Geneva, Paris and São Paulo are presented. The experimental research uses field measurements for collecting microclimatic data and computer simulations with the ENVI-met model, which allowed the comparison of current and alternative scenarios. All simulations were carried out for summer conditions. The thermal comfort indices Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) were used to assess levels of thermal stress at the pedestrian level. In general, it was observed that the insertion of green areas (particularly under dense canopy) could reduce the daytime heating in urban areas...

Medidas físicas e biológicas com potencial para uso em recuperação de voçoroca no município de Uberlândia-MG

Silva, Alcione Hermínia da
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Dissertação
Português
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Em conseqüência do manejo inadequado do solo no Bioma Cerrado, atualmente áreas rurais e urbanas encontram-se com elevado grau de degradação. Assim, a Mesorregião do Triângulo Mineiro está entre os locais do Brasil com maior ocorrência de processos erosivos em forma de voçorocas. O presente trabalho objetivou avaliar a eficiência de um conjunto de práticas simples e de baixo custo, para estabilização e recuperação de voçorocas na Fazenda Glória em Uberlândia-MG. Para tanto, foram analisadas algumas características pedológicas (físicas e químicas) ligadas ao voçorocamento, bem como, estruturas físicas (terraços de base estreita e mulching vertical); paliçadas de bambu com sacos de ráfia e biológicas (revegetação com leguminosas arbóreas e herbáceas). As técnicas foram implantadas nas áreas internas e externas das incisões erosivas, onde procurou-se unir durante o período do estudo (um ano e meio) subsídios que contemplassem indicadores da mudança da paisagem. Para avaliação biológica/edáfica, a variável analisada na parte interna foi a comparação das médias de desenvolvimento entre duas espécies herbáceas. Na parte externa foi analisado o estabelecimento de espécies arbóreas sob diferentes doses de corretivo do solo...

An Analysis of Physical and Monetary Losses of Environmental Health and Natural Resources in India

Mani, Muthukumara; Markandya, Anil; Sagar, Aarsi; Strukova, Elena
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
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27.219314%
This study provides estimates of social and financial costs of environmental damage in India from three pollution damage categories: (i) urban air pollution; (ii) inadequate water supply, poor sanitation, and hygiene; and (iii) indoor air pollution. It also provides estimates based on three natural resource damage categories: (i) agricultural damage from soil salinity, water logging, and soil erosion; (ii) rangeland degradation; and (iii) deforestation. The estimates are based on a combination of Indian data from secondary sources and on the transfer of unit costs of pollution from a range of national and international studies. The study estimates the total cost of environmental degradation in India at about 3.75 trillion rupees (US$80 billion) annually, equivalent to 5.7 percent of gross domestic product in 2009, which is the reference year for most of the damage estimates. Of this total, outdoor air pollution accounts for 1.1 trillion rupees, followed by the cost of indoor air pollution at 0.9 trillion rupees...

Toward Cleaner Urban Air in South Asia: Tackling Transport Pollution, Understanding Sources

World Bank
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
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26.799502%
This ESMAP study was undertaken to provide technical input to support the region-wide process of developing and adopting cost-effective and realistic policies and efficient enforcement mechanisms to reverse the deteriorating trend in urban air quality in South Asia. It focused mainly on fine particulate matter, estimated to account for most premature mortality and illnesses caused by outdoor air pollution. Through stakeholder feedback, the study examined two areas where more information and policy analysis could complement ongoing activities on air pollution control: making vehicle emissions inspection more effective and understanding sources of small particulate matter. Poorly maintained older technology vehicles contribute disproportionately to total vehicular emissions. A common approach to identifying gross polluters and ensuring that they are repaired or retired is a vehicle inspection and maintenance (I/M) program. The analysis carried out in this study recommends that limited resources be concentrated on applying more robust (but also costly) test protocols to vehicle categories in large cities likely to contain a disproportionately large fraction of high annual-kilometer...

Resistance to acetolactate synthase-inhibiting herbicides in Sonchus oleraceus, Sisymbrium orientale and Brassica tournefortii / Peter Boutsalis.

Boutsalis, Peter
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 136465 bytes; application/pdf
Publicado em //1996 Português
Relevância na Pesquisa
27.188079%
The aim of this thesis is to confirm the resistance status of three purported resistant weed species by herbicide screening of outdoor pot grown plants. Field experiments are set up to investigate changes in dormancy and seedbank life of the resistant populations over a three year period. After determining the herbicide resistance spectrum of the resistant biotypes, genetic crosses between resistant and susceptible plants are performed to follow the mode of inheritance of acetolactate synthase (ALS) resistance. "In vitro" ALS enzyme assays in the presence of various herbicides are carried out to reveal a modified ALS enzyme as the main mechanism of resistance in all cases. A molecular investigation of the ALS gene is performed to identify mutations responsible for endowing a resistant enzyme.; Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 1996; Bibliography: leaves 147-163.; ix, 164 leaves : ill. (some col.) ; 30 cm.; Title page, contents and abstract only. The complete thesis in print form is available from the University Library.

Cleaning Pakistan's Air : Policy Options to Address the Cost of Outdoor Air Pollution

Sanchez-Triana, Ernesto; Enriquez, Santiago; Afzal, Javaid; Nakagawa, Akiko; Khan, Asif Shuja
Fonte: Washington, DC: World Bank Publicador: Washington, DC: World Bank
Tipo: Publications & Research :: Publication
Português
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Pakistan's urban air pollution is among the most severe in the world and it engenders significant damages to human health and the economy. Air pollution, inadequate water supply, sanitation, and hygiene are the top environmental priority problems in Pakistan. Industrialization and urbanization, in conjunction with motorization, can result in further deterioration of urban air quality. This book examines policy options to strengthen the Pakistan clean air program (PCAP) to better address the cost imposed by outdoor air pollution upon Pakistan's economy and populace. The approach provided in this book recommends that the federal and provincial environmental protection agencies (EPAs) take on a limited number of high return, essential, and feasible interventions drawn largely from the PCAP. The objective of this book is to examine policy options to control outdoor air pollution in Pakistan. The findings of the analysis aim at assisting the Government of Pakistan (GoP) in the design and implementation of reforms to improve the effectiveness and efficiency of Pakistan's ambient air quality institutions. The overarching theme of this book is that prioritizing interventions is essential to address the cost of outdoor air pollution...

Detection of Achromobacter xylosoxidans in Hospital, Domestic, and Outdoor Environmental Samples and Comparison with Human Clinical Isolates

Amoureux, Lucie; Bador, Julien; Fardeheb, Sakina; Mabille, Cédric; Couchot, Charlyne; Massip, Clémence; Salignon, Anne-Lise; Berlie, Guillaume; Varin, Véronique; Neuwirth, Catherine
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /12/2013 Português
Relevância na Pesquisa
27.574536%
Achromobacter xylosoxidans is an aerobic nonfermentative Gram-negative rod considered an important emerging pathogen among cystic fibrosis (CF) patients worldwide and among immunocompromised patients. This increased prevalence remains unexplained, and to date no environmental reservoir has been identified. The aim of this study was to identify potential reservoirs of A. xylosoxidans in hospital, domestic, and outdoor environments and to compare the isolates with clinical ones. From 2011 to 2012, 339 samples were collected in Dijon's university hospital, in healthy volunteers' homes in the Dijon area, and in the outdoor environment in Burgundy (soil, water, mud, and plants). We designed a protocol to detect A. xylosoxidans in environmental samples based on a selective medium: MCXVAA (MacConkey agar supplemented with xylose, vancomycin, aztreonam, and amphotericin B). Susceptibility testing, genotypic analysis by pulsed-field gel electrophoresis, and blaOXA-114 sequencing were performed on the isolates. A total of 50 strains of A. xylosoxidans were detected in hospital (33 isolates), domestic (9 isolates), and outdoor (8 isolates) samples, mainly in hand washing sinks, showers, and water. Most of them were resistant to ciprofloxacin (49 strains). Genotypic analysis and blaOXA-114 sequencing revealed a wide diversity among the isolates...

Influencia de las macrófitas flotantes en la comunidad fitoplanctónica en un humedal del bajo Paraná (Reserva natural de Otamendi, Argentina; Influence of the free floating plants on the phytoplankton community in a wetland from the lower Parana (Otamendi natural reserve, Argentina)

de Tezanos Pinto, Paula
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2008 Português
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37.188079%
Se analizaron los efectos de las plantas flotantes libres (PFL) sobre la ecología del fitoplancton a través de experimentos en microcosmos en laboratorio y en mesocosmos en el campo, además de un relevamiento en un ecosistema frecuentemente vegetado con PFL. La cubierta de PFL determinó una columna de agua cuasi oscura y anóxica, que generó liberación de nutrientes desde los sedimentos. La fuerte limitación por luz ejerció un intenso control sobre la biomasa fitoplanctónica, generando ensambles con baja riqueza, pero elevada diversidad y de similar composición específica. Si bien la disponibilidad de nutrientes jugó un rol menor en modelar la respuesta ecológica fitoplanctónica, ésta generó respuestas fisiológicas diferentes. Por el contrario, en ausencia de PFL (mejor clima lumínico) la biomasa fitoplanctónica fue elevada, el oxígeno alcanzó valores de sobresaturación y los nutrientes fueron activamente consumidos. En estos escenarios bien iluminados, los niveles y la relación de nutrientes jugaron un rol fundamental en la estructuración de la composición y la abundancia algal. Así, en altas relaciones de nitrógeno: fósforo (N:P) dominaron especies de la clase Chlorophyceae, mientras que en bajas relaciones de N:P prevalecieron las cianobacterias fijadoras de nitrógeno. La fluctuación periódica en la cobertura de PFL generó una rápida respuesta del ambiente fisicoquímico...

Physiological responses of apricot plants grafted on two different rootstocks to flooding conditions

Domingo Miguel, Rafael; Pérez-Pastor, A.; Ruiz Sánchez, Mª Carmen
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 213969 bytes; application/pdf
Português
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The effects of soil flooding on plant water relations and vegetative growth was studied in potted two-year-old apricot plants (Prunus armeniaca L., cv. Búlida) grafted on two different rootstocks: Pollizo prune (P. insititia L.) (P) and Real Fino apricot (RF). Plants were submitted to three outdoor treatments: T0, not flooded (control), and two flooded treatments for 3 (T1) and 6 (T2) days. Apricot water relations were seen to be adversely affected from the first day of the flooding onwards. These effects were more pronounced in Búlida/RF than in Búlida/P plants. The T1 plants developed an early stomatal regulation [decrease in leaf conductance (gl)], which prevented leaf tissue dehydration, together with a decrease in net photosynthesis (Pn) and an increase in resistance to water flow (R(p+s)). This early gl and Pn response suggests that porometric and/or photosynthetic changes are reliable bio-indicators of the altered behaviour caused by flooding in apricot plants. The lowest gl and Pn, and highest R(p+s) values occurred with more prolonged flooding (6 days), when a decrease in leaf water potential (ψl) and leaf turgor was noted, together with epinasty, which in Búlida/RF plants led to a decrease in ψl to -6.0 MPa, and the death of all plants. These results indicate Búlida apricot plants grafted onto Pollizo prune rootstock is a more appropriate combination than Búlida/Real Fino to resist occasional soil flooding situations.; The study was supported by CICYT (HID1999- 0951; AGL2000-0387-C05-04) grants to the authors.; Peer reviewed