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| Registros recuperados: 218 | |
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| FERREIRA,Débora Najara de SOUZA; CAMARGO,José Luís Campana; FERRAZ,Isolde Dorothea Kossmann. |
| ABSTRACT Polyembryony is the differentiation and development of multiple embryos in a single seed. This characteristic can provide advantages, as more than one embryo is produced with the same amount of resources, and the probability of establishment of at least one seedling increases. However, sibling seedlings may also increase competition, affecting development and survival. In the present study, the possible advantages and disadvantages of polyembryony were analyzed in the initial establishment of seedlings of Carapa surinamensis (Meliaceae), a tree species that produces monoembryonic or polyembryonic seeds. In this regard, the development of single seedlings was compared with a pair of seedlings emerging from polyembryonic seeds. We compared the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Polyembryony; Andiroba; Crabwood; Seedling production; Competition. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0044-59672019000200097 |
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| CESA-LUNA,Catherine; BAEZ,Antonino; QUINTERO-HERNÁNDEZ,Verónica; CRUZ-ENRÍQUEZ,Joel DE LA; CASTAÑEDA-ANTONIO,Ma Dolores; MUÑOZ-ROJAS,Jesús. |
| ABSTRACT Bacteria produce antimicrobial compounds to compete for nutrients and space in a particular habitat. Antagonistic interactions can be evaluated by several methodologies including the double-layer agar and simultaneous inhibition assays. Among the well-known inhibitory substances produced by bacteria are the broad-spectrum antibiotics, organic acids, siderophores, antifungal, and bacteriocins. The most studied bacterial genera able to produce these inhibitory substances are Enterococcus, Lactococcus, Streptomyces, Bacillus, Pseudomonas, Klebsiella, Escherichia, and Burkholderia. Some beneficial bacteria can promote plant growth and degrade toxic compounds in the environment representing an attractive solution to diverse issues in agriculture and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Antagonism; Antibiotic; Competition; Inhibition; PGPR. |
| Ano: 2020 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2020000100140 |
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| Reigosa,Manuel; Gomes,Anabele Stefânia; Ferreira,Alfredo Gui; Borghetti,Fabian. |
| In this article, we review allelopathy studies conducted in Brazil or involving plant species that occur in the country. Conceptions and misconceptions associated with allelopathy, as well as some international criteria to be applied in allelopathic research, are presented and discussed. We observed a sharp increase in the number of papers on this subject conducted in Brazil between 1991 and 2010. However, most studies are conducted under laboratory conditions, lack a clear hypothesis or a solid justification, and typically make use of target species that do not co-exist with the donor species under natural conditions. We also found that most studies do not take the additional steps in order to purify and identify the bioactive molecules. We recommend that... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Allelopathy; Allelochemicals; Competition; Interference; Phytotoxicity; Weed control. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062013000400001 |
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| Souza,Sthefanie do Nascimento Gomes de; Piedade,Maria Teresa Fernandez; Demarchi,Layon Oreste; Lopes,Aline. |
| ABSTRACT Amazon wetlands are among the most vulnerable ecosystem to be impacted by climate change, which may increase the frequency of extreme droughts and floods. We used Eichhornia crassipes and Pistia stratiotes, two abundant aquatic plants in the Amazon floodplains, to evaluate the effects of combined temperature and [CO2] increase on growth, physiology and ecological interactions. Individual and paired plants were deposited for three weeks in a microcosm under four IPCC scenarios: control (current temperature/CO2), mild (control + 1.5 ºC, 200 ppm CO2), intermediate (control + 2.5 ºC, 450 ppm CO2) and extreme (control + 3.5 ºC, 850 ppm CO2). P. stratiotes died after three weeks in the intermediate and extreme treatments; E. crassipes experienced no... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biomass; Competition; Eichhornia crassipes; Pistia stratiotes; Wetlands. |
| Ano: 2021 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062021005002204 |
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| Mesquita,Mário Luiz Ribeiro; Andrade,Leonaldo Alves de; Pereira,Walter Esfrain. |
| The objective of this study was to compare the ex situ and in situ floristic diversity of the soil weed seed bank of a rice field in northeastern Brazil. In a rice field in the county of Bacabal, located in the state of Maranhão, thirty 25-m² plots were laid out. From 15 plots, soil samples (6/plot; n = 90) were taken with a soil probe (25 × 16 × 3 cm) and placed in aluminum trays in the greenhouse. From the remaining 15 plots, weed samples (6/plot; n = 90) were taken with the same soil probe. The number of seeds was estimated by germination. We evaluated the numbers of species and individuals, as well as the density, frequency, abundance and importance value (IV) for each species. Diversity was computed by the Shannon index (H'). We recorded 13,892... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cyperaceae; Competition; Biological invasion; Phytosociology; Smallholder farmers. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062013000300001 |
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| Gastauer,Markus; Saporetti-Junior,Amílcar W.; Valladares,Fernando; Meira-Neto,João A. A.. |
| ABSTRACT Mussununga, an oligotrophic sandy savanna ecosystem, comprises distinct physiognomies along fire, water and nutrient availability gradients. Grasslands and woodlands are constrained at the opposite poles of these gradients, with grasslands occurring in areas with poorer soils and higher levels of both water-stress and fire intensity. According to the stress-dominance hypothesis, one might expect the importance of competition for community assembly to increase from grasslands to woodlands. Assuming conservation of ecological niches within evolutionary lineages, this should increase phylogenetic overdispersion from grasslands towards woodlands. To test this, we calculated phylogenetic diversity and community structure using different null models as... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Competition; Environmental filters; Mussunungas; Savanna woodlands; Stress-dominance hypothesis. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062017000400531 |
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| Scholten, Roger; Unesp-Jaboticabal; Parreira, Mariana Casari; Unesp-Jaboticabal; Alves, Pedro Luis da Costa Aguiar; Unesp-Jaboticabal. |
| Os feijões estão entre os alimentos mais antigos, fazendo parte da alimentação diária da população brasileira. Objetivou-se com este trabalho determinar o período de convivência anterior à interferência das plantas daninhas (PAI) na cultura do feijoeiro em diferentes espaçamentos e densidades de plantas. Os tratamentos foram constituídos de períodos de convivência entre a cultura e as plantas daninhas, sendo zero a dez, zero a 20, zero a 30, zero a 40, zero a 50, zero a 60, zero a 70 e zero a 80 dias e mais uma testemunha sem convívio com as plantas daninhas. Além dos períodos de convivência, realizaram-se ainda estudos com espaçamentos entre linhas de 0,45 e 0,60 m e mais duas densidades de semeadura: dez e 15 plantas m-1. Adotou-se delineamento... |
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Palavras-chave: Phaseolus vulgaris; Competição; Períodos de controle Phaseolus vulgari; Competition; Control periods. |
| Ano: 2011 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/5646 |
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| Mesquita, Mário Luiz Ribeiro; Andrade, Leonaldo Alves; Pereira, Walter Esfrain. |
| The objective of this research was to assess the density, floristic composition, phytosociology and diversity of a soil weed seed bank ex situ by germination in a greenhouse and in situ by weed sampling on a smallholder corn field located in Lago Verde County, Maranhão State. Fifteen pairs of 25 m2 plots were designated. In half of these plots, 90 soil samples were collected with an open metal template measuring 25 x 16 x 3 cm and placed in a greenhouse to germinate. In the other half, 90 weed samples were collected using the same metal template. We recorded a total of 1,998 individuals from 40 species, 31 genera and 16 families, from which 659 individuals germinated in situ and 1,339 exsitu. Density was higher ex situ, with 372 plants m-2. The Cyperaceae... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ciências Agrárias Fitotecnia cyperaceae; Competition; Biological invasion; Phytosociology; Smallholder farmers Botânica Sistemática Plantas Invasoras. |
| Ano: 2014 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/19360 |
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| SÁ-OLIVEIRA,JÚLIO C.; ANGELINI,RONALDO; ISAAC-NAHUM,VICTORIA J.. |
| We investigated the niche breadth and overlap of the fish species occurring in four environments affected by the Coaracy Nunes reservoir, in the Amapá Brazilian State. Seasonal samples of fishes were taken using a standard configuration of gillnets, as well as dragnets, lines, and castnets. Five hundred and forty stomach contents, representing 47 fish species were analyzed and quantified. Niche breadth and overlap were estimated using indexes of Levins and Pianka, respectively, while interspecific competition was evaluated using a null model (RA3). ANOVA and the KruskalWallis test were used, respectively, to evaluate differences in niche breadth and overlap between areas. The data indicate that the majority of the fish species belong to the piscivore,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Competition; Neotropical reservoir; Diet; Species coexistence. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000100383 |
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| BARBOSA,LEANDRO S.; COURI,MÁRCIA S.; COELHO,VALÉRIA M.A.; AVELINO-CAPISTRANO,FERNANDA. |
| ABSTRACT The classic episode of biological invasion: Cochliomyia macellaria (Fabricius, 1775) versus Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) - evaluation of the biotic potential. The biotic of the native fly Cochliomyia macellaria and the exotic Chrysomya megacephala was compared, through the reproductive capacity and longevity. The experiment took place in a climatized chamber, with four repetitions of 15 grouped couples of each species. The posture, egg mass weight, and death of individuals were observed daily. C. macellaria showed an average of longevity of 27.72 days while in C. megacephala the average was 41.96 days. The egg mass weight average per repetition was 0.58 g and 1.22 g, respectively. These results give a better... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Breed capacity; Longevity; Competition; Caliphorids.. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000401401 |
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| CARON,BRAULIO O.; ELLI,ELVIS F.; BEHLING,ALEXANDRE; ELOY,ELDER; SCHMIDT,DENISE; STOLZLE,JOHN. |
| Abstract The appropriate choice of tree species and planting arrangement for use in agroforestry systems is very important in order to maximize productivity and sustainability. The aim of this study was to evaluate the growth of five tree species and its effect on sugarcane yields in different planting arrays in agroforestry systems. The study was conducted from 2007 to 2011 in the city of Frederico Westphalen, RS, Brazil. The five studied tree species were: guapuruvu (Schizolobium parahybae), bracatinga (Mimosa scabrella), canafístula (Peltophorum dubium), angico-vermelho (Parapiptadenia rigida) and eucalypt (Eucalyptus urophylla S.T. Blake x Eucalyptus grandis Hill ex Maiden). Root collar diameter, diameter at breast height, plant height and mean... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Array of plants; Competition; Crown diameter; Height. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652018000502425 |
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| ARREDONDO,MIGUEL; MARTÍNEZ,RONNY; NÚÑEZ,MARCO T; RUZ,MANUEL; OLIVARES,MANUEL. |
| Interactions of micronutrients can affect absorption and bioavailability of other nutrients by a number of mechanisms. In aqueous solutions, and at higher uptake levels, competition between elements with similar chemical characteristics and uptake process can take place. The consequences of these interactions may depend on the relative concentrations of the nutrients. In this work, we measure the effects of increasing concentrations of iron, zinc, and copper on iron and copper uptake in Caco-2 cells. Intracellular Fe or Cu levels were affected by incubating with increased concentrations of metals. However, when the cells already had different intracellular metal concentration, the uptake of Fe or Cu was nor affected. In competition studies, we showed that... |
| Tipo: Journal article |
Palavras-chave: Competition; Interaction; Metals; Uptake. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000100011 |
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| Bastiani,Marlon Ouriques; Lamego,Fabiane Pinto; Agostinetto,Dirceu; Langaro,Ana Claudia; Silva,Diônvera Coelho da. |
| ABSTRACT The aim of this work was to evaluate the competitiveness between soybean cultivars and barnyardgrass, based on morphological and physiological characteristics of species. The experiments were conducted in completely randomized experimental design, with 4 replications. In the first study, for both soybean and barnyardgrass, it was determined the population of plants in which shoot dry matter became constant and independent of the population (16 plants∙pot−1 or 400 plants∙m−2). In the second study, 2 experiments were conducted to evaluate the competitiveness of BMX Apolo RR and BMX Potência RR soybean cultivars with barnyardgrass plants, both carried out in replacement series under different proportions of plants∙pot−1 (100:0; 75:25; 50:50; 25:75... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Echinochloa crus-galli; Lowlands; Replacement series; Competition. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052016000400435 |
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| Galon,Leandro; Basso,Felipe José Menin; Chechi,Leonardo; Pilla,Thalita Pedrozo; Santin,Carlos Orestes; Bagnara,Maico André Michelon; Franceschetti,Milena Barretta; Castoldi,Camile Thaís; Perin,Gismael Francisco; Forte,César Tiago. |
| ABSTRACT The study of weed interference periods and the economic threshold level (ETL) of weeds on crops allows the adoption of management methods and the rationalized use of herbicides. The objective of this study was to determine the periods of interference and to test mathematical models to determine the economic threshold level of ryegrass in the wheat crop. Two experiments were carried out in a randomized block design with four replications. The first experiment was conducted in the 2014/2015 agricultural season. The periods of interference and control of ryegrass were studied in wheat. The periods of interference and/or control were: 0, 10, 20, 30, 40, 50 and 120 days after emergence (DAE). The second experiment was conducted in the 2016/2017... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Triticum aestivum; Lolium multiflorum; Competition. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052019000300409 |
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| Registros recuperados: 218 | |
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