Efeito do hexazinone isolado e em mistura na eficiência fotossintética de Panicum maximum
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Data
2012-06-01
Autores
Girotto, M.
Araldi, R.
Velini, Edivaldo Domingues [UNESP]
Trindade, M. L. B.
Carbonari, Caio Antonio [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira da Ciência das Plantas Daninhas
Resumo
Esta pesquisa teve como objetivo avaliar a velocidade e intensidade de ação do hexazinone isolado e em mistura com outros inibidores do fotossistema II, através da eficiência fotossintética de Panicum maximum em pós-emergência. O ensaio foi constituído de seis tratamentos: hexazinone (250 g ha-1), tebuthiuron (1,0 kg ha-1), hexazinone + tebuthiuron (125 g ha-1 + 0,5 kg ha-1), diuron (2.400 g ha-1), hexazinone + diuron (125 + 1.200 g ha-1), metribuzin (1.440 g ha-1), hexazinone + metribuzin (125 + 720 g ha-1) e uma testemunha. O experimento foi instalado em delineamento inteiramente casualizado, com quatro repetições. Após a aplicação dos tratamentos, as plantas foram transportadas para casa de vegetação sob condições controladas de temperatura e umidade, onde ficaram durante o período experimental, sendo realizadas as seguintes avaliações: taxa de transporte de elétrons e análise visual de intoxicação. A avaliação com o fluorômetro foi realizada nos intervalos de 1, 2, 6, 24, 48, 72, 120 e 168 horas após a aplicação, e as avaliações visuais, aos três e sete dias após a aplicação. Os resultados demonstraram diferença nos tratamentos, enfatizando a aplicação do diuron, que reduziu lentamente o transporte de elétrons comparado com os outros herbicidas e, em mistura com hexazinone, apresentou efeito sinérgico. Verificou-se com o uso do fluorômetro a intoxicação antecipada em plantas de P. maximum após a aplicação de herbicidas inibidores do fotossistema II de forma isolada e em mistura.
This work aimed to evaluate the speed and intensity of action of hexazinone applied alone and in combination with other photo-system II inhibitors on the photosynthetic efficiency of Panicum maximum in post-emergence. The assay consisted of six treatments: hexazinone (250 g ha-1), tebuthiuron (1.0 kg ha-1), hexazinone + tebuthiuron (125 g ha-1+ 0.5 kg ha-1), diuron (2,400 g ha-1), hexazinone + diuron (125 + 1,200 g ha-1), metribuzin (1,440 g ha-1), hexazinone + metribuzin (125 + 720 g ha-1) and a control. The experiment was conducted in a randomized design with four replications. After treatment application, plants were transported to a greenhouse with controlled temperature and humidity, remaining there throughout the experimental period, during which electron transport rate and visual analysis of intoxication were assessed. The fluorometer evaluation was performed at intervals of01, 02, 06, 24, 48, 72, 120, and168 hours after application, and visual assessments at 3 and 7 days after application. The results showed differences in the treatments, with the application ofthe herbicide diuron slowly reducing electron transport, compared with the other herbicides, and presenting a synergistic effect when mixed with hexazinone. Early intoxication of P. maximum plants was verified with the use ofthe fluorometer, after application of the photo-system IIinhibitors, alone and in combination.
This work aimed to evaluate the speed and intensity of action of hexazinone applied alone and in combination with other photo-system II inhibitors on the photosynthetic efficiency of Panicum maximum in post-emergence. The assay consisted of six treatments: hexazinone (250 g ha-1), tebuthiuron (1.0 kg ha-1), hexazinone + tebuthiuron (125 g ha-1+ 0.5 kg ha-1), diuron (2,400 g ha-1), hexazinone + diuron (125 + 1,200 g ha-1), metribuzin (1,440 g ha-1), hexazinone + metribuzin (125 + 720 g ha-1) and a control. The experiment was conducted in a randomized design with four replications. After treatment application, plants were transported to a greenhouse with controlled temperature and humidity, remaining there throughout the experimental period, during which electron transport rate and visual analysis of intoxication were assessed. The fluorometer evaluation was performed at intervals of01, 02, 06, 24, 48, 72, 120, and168 hours after application, and visual assessments at 3 and 7 days after application. The results showed differences in the treatments, with the application ofthe herbicide diuron slowly reducing electron transport, compared with the other herbicides, and presenting a synergistic effect when mixed with hexazinone. Early intoxication of P. maximum plants was verified with the use ofthe fluorometer, after application of the photo-system IIinhibitors, alone and in combination.
Descrição
Palavras-chave
fluorescência, fluxo de elétrons, fotossistema, fluorômetro, fluorescence, electron flow, photo-system, fluorometer
Como citar
Planta Daninha. Sociedade Brasileira da Ciência das Plantas Daninhas , v. 30, n. 2, p. 341-347, 2012.