Temperatura e luz na germinação das sementes de apaga-fogo (Alternanthera tenella)

Canossa, Rosecler Salete; Oliveira, Rubem Silvério de; Constantin, Jamil; Braccini, Alessandro Lucca; Biffe, Denis Fernando; Alonso, Diego Gonçalves; Blainski, Éverton

doi:10.1590/s0100-83582008000400005

Cited by 21 publications

(14 citation statements)

References 17 publications

(14 reference statements)

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“…It is considered a species that emerges late during the summer, and usually does not interfere in (Canossa et al, 2008). Such behavior was observed in this study; A. tenella did not show an excess RIm index during the summer season as in the fall, due its seasonal growth habit (Figures 1 and 3).…”

Section: Fall Field Trialsupporting

confidence: 77%

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Weed Community Interference and Phytosociological Studies in a Sweet Sorghum Crop

et al. 2017

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-This research was carried out to evaluate the interference periods and phytosociological indexes of the weed community on sweet sorghum, hybrid CVSW 80007, cultivated for two seasons in a year. The treatments were based on an increased duration of weed presence and weed absence after sowing (0, 4, 7, 14, 21, 28, 35, 42, 56 and 68 days after crop emergence for the summer season and 0, 4, 7, 14, 21, 28, 35, 42, 49, 56, 63 and 100 days for the fall season). The weed community was evaluated based on the number of weeds and the dry mass of each weed population in each period of weed control in the summer season and each period of no weed control and weed control in the autumn season. These data were used to determine the relative indexes of density, dominance and importance, and the weed community indexes of diversity and equitability. The main weeds comprising the community were Cyperus rotundus, Alternanthera tenella, Indigofera hirsuta, Amaranthus sp., Digitaria nuda, and Portulaca oleracea. The weed density was found to be the primary factor for the importance of weeds in the community, once their development and biomass accumulation were suppressed by the sweet sorghum competition. The sweet sorghum hybrid proved highly competitive and, in the agro-ecological conditions of the trials, weed interference did not reduce crop yield.Keywords: Sorghum bicolor, weeds, weed competition. (0, 4, 7, 14, 21, 28, 35, 42, 56 e 68 dias após a emergência da cultura na safra de verão e 0, 4, 7, 14, 21, 28, 35, 42, 49, 56, 63 RESUMO -Este estudo teve por objetivo determinar os períodos de interferência e índices fitossociológicos da comunidade infestante da cultura do sorgo-sacarino, híbrido CVSW 80007, cultivado em duas épocas do ano. Os tratamentos consistiram de períodos crescentes de presença ou ausência da comunidade infestante

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Section: Fall Field Trialsupporting

confidence: 77%

“…Alternanthera tenella is an important weed in agriculture, due to its rapid dissemination and high density of infestation, especially in the Cerrado ecoregion (Canossa et al, 2008). It is considered a species that emerges late during the summer, and usually does not interfere in (Canossa et al, 2008).…”

Section: Fall Field Trialmentioning

confidence: 99%

Weed Community Interference and Phytosociological Studies in a Sweet Sorghum Crop

et al. 2017

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“…A falta de algum desses fatores pode fazer com que a germinação ocorra de forma lenta e em menor escala, ou ainda, induzir à dormência (Canossa et al, 2008). Temperatura e luz são considerados os sinais ambientais que regulam a germinação, distribuição das espécies e interações ecológicas (Ali et al, 2013), quando a umidade do solo é suficiente para embebição da semente, pois a água faz parte das estruturas moleculares como proteínas e ácidos nucleicos, bem como de lipídeos e carboidratos (Guimarães et al, 2008).…”

Section: Fatores Ambientais Que Influenciam O Fluxo De Emergênciaunclassified

Modelagem matemática do fluxo de emergência de plantas daninhas: ferramenta para decisão no manejo de cultivos

2018

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Resumo -O surgimento de biótipos de plantas daninhas resistentes a herbicida e o aumento da pressão social para reduzir sua utilização, criou a necessidade de desenvolver ferramentas para aperfeiçoar a aplicação de herbicidas e melhorar o controle de plantas daninhas. Desta forma, o desenvolvimento de modelos de emergência de plantas daninhas tornou-se crucial para o desenvolvimento de estratégias de gerenciamento em áreas agrícolas. Esta revisão tem por objetivo apresentar os fatores que influenciam o fluxo de emergência de plantas daninhas, os principais modelos utilizados, os procedimentos da modelagem e os impactos práticos de sua utilização no manejo. O fluxo de emergência das plantas daninhas correlaciona-se diretamente com padrões de resposta das sementes à interferência dos fatores ambientais e práticas culturais. Os modelos de emergência empíricos e mecanicistas desenvolvidos permitem prever a emergência de plantas daninhas em diferentes anos e regiões geográficas, baseados em condições climáticas e ecofisiológicas. Os modelos mecanicistas são mais complexos e permitem a melhor compreensão sobre a emergência de plantas daninhas, enquanto modelos empíricos apresentam a simplicidade e a flexibilidade necessária para a tomada de decisão de controle. O conhecimento do fluxo de emergência de plantas daninhas permite desenvolver estratégias de manejo que proporcionam maior habilidade competitiva à cultura e, em decorrência, menores perdas de produtividade; bem como a seleção de medidas de controle que diminuam a utilização de herbicidas, a contaminação ambiental e aprimorem as tecnologias utilizadas na agricultura. Palavras-chave: modelo empírico, gerenciamento, tempo hidrotérmico Abstract -The appearance of weed biotypes resistant to herbicides and the increase in social pressure to reduce its use, created the need to develop tools to refine herbicides application and improve weed control. In this way, the development of weed emergence models has become crucial for the development of management strategies in agricultural areas. The objective of this review is to show the factors that influence the emergence flow and the main models used to predict weed emergence, the procedures of modeling and the practical impacts of their use for weed management. The emergence flow of weeds correlates directly with seed response patterns to the interference of environmental factors and cultural practices. The developed empirical and mechanistic emergence models allow predict weeds emergence in different years and geographic regions, based on climatic and ecophysiological conditions. However, mechanistic models are more complex and allow better

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“…Studies conducted by Canossa et al (2008), investigating the germination process of joyweed, reported that the species germinates both in the presence and the absence of sunlight, however, its germination is favored by the presence of light and by higher temperatures. This fact may be the reason why only on castor bean monocultures the joyweed species stood out in terms of importance in relation to buffelgrass, since castor beans have a C3 photosynthesis cycle, with slow initial growth, which, allied to the spacing used (3 x 1 m in between the rows and between the plants), allowed a greater incidence of solar radiation on the soil, offering the temperature and luminosity for the species to germinate; on systems in which common bean was used, the presence of this culture promoted greater soil shading, contributing to a reduced sunlight incidence and, consequently, to a lower temperature.…”

Section: (A) (B)mentioning

confidence: 99%

Phytosociological Survey of Weed Plants in Intercrops of Common Beans and Castor Beans

et al. 2017

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-The aim of this paper was to conduct the phytosociological survey of weeds in cultivated areas with common beans and castor beans in the municipality of Ipameri, in the Southeast region of the State of Goiás, considering intercropping and monoculture. The survey was conducted 20 days after emergence of the crop using the square inventory method. We evaluated the green and dry biomass of weeds, their leaf area, frequencies, density and absolute and relative dominance, relative importance and similarity index, expressed as a percentage. Sixteen weed species were identified, distributed into 10 botanical families. The most important weed species in the Southeast region of Goiás for the cultivation of common beans and castor beans were: Cenchrus echinatus, Euphorbia heterophylla, Alternanthera tenella, Eleusine indica and Urochloa decumbens. The weed community shows a high level of similarity between intercropping and monoculture for castor bean and common bean crops. Keywords: Phaseolus vulgaris, Ricinus communis, intercropping, phytosociology. RESUMO -Objetivou-se com este trabalho realizar o levantamento fitossociológico de plantas daninhas em área cultivadas com feijão e mamona no município de

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Temperatura e luz na germinação das sementes de apaga-fogo (Alternanthera tenella)

Cited by 21 publications

References 17 publications

Weed Community Interference and Phytosociological Studies in a Sweet Sorghum Crop

Weed Community Interference and Phytosociological Studies in a Sweet Sorghum Crop

Modelagem matemática do fluxo de emergência de plantas daninhas: ferramenta para decisão no manejo de cultivos

Phytosociological Survey of Weed Plants in Intercrops of Common Beans and Castor Beans

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