Cassava physiological responses to the application of herbicides

Autor: Evander Alves Ferreira, Christiano da Conceição de Matos, Edmilson Alves Barbosa, Daniel Valadão Silva, José Barbosa dos Santos, Gustavo Antonio Mendes Pereira, Autieres Teixeira Faria, Cícero Teixeira da Silva
Jazyk: English<br />Portuguese
Rok vydání: 2015
Předmět:
Zdroj: Semina: Ciências Agrárias, Vol 36, Iss 2, Pp 645-656 (2015)
Druh dokumentu: article
ISSN: 1679-0359
1676-546X
DOI: 10.5433/1679-0359.2015v36n2p645
Popis: Analysis of chlorophyll a fluorescence has been used to improve the understanding of the mechanisms of photosynthesis, as well as in the evaluation of plant photosynthetic capacity altered by biotic or abiotic stresses. The objective of this study was to evaluate the sensitivity of cassava plants to herbicides with different mechanisms of action, as well as the damage caused by the application of herbicides on the photosynthetic apparatus of these plants. An experiment was conducted in a randomized block design with four replications. The treatments were constituted of the application of the following post- emergence herbicides in cassava: bentazon, clomazone, fomesafen, fluazifop-p-buthyl, glyphosate, nicosulfuron, chlorimuron, fluazifop-p-buthyl + fomesafen, sulfentrazone, besides a control without application. The visual intoxication and chlorophyll a fluorescence assessments were performed at 2, 9, 16 and 23 days after herbicide application. The herbicides evaluated affected differently the cassava plants. Sulfentrazone and glyphosate promoted plant death. Herbicides clomazone, fomesafen, fluazifop-p-buthyl and chlorimuron-ehtyl caused low toxicity to cassava plants and did not affect the ratio Fv / Fm and ETR. However, for the mixture nicossulfuron and fluazifop-p-buthyl + fomesafen values of Fv / Fm were suboptimal in the first evaluation times but plants treated with these herbicides had recovered. Physiological evaluations can be used as a way to evaluate the selectivity of herbicides in cassava crop as presented similar answers to those observed for visual intoxication symptoms.
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