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In the present study, two strains of Ectocarpus siliculosus with different pollution histories, LIA4 and Es524, were exposed to three PSII inhibitor herbicides, diuron (DIU), terbuthylazine (TBA) and isoproturon (IPU). Evaluation of their effects on growth and photosynthetic efficiency (Fv/Fm, ΦPSII, qP) have demonstrated negative impacts of all herbicides on both strains. With reference to the 7 d RGR EC50 values; DIU (9.9 - 25 μg L-1); TBA (18 – 28 μg L-1); IPU (257 – 315 μg L-1), the reported environmental concentrations for DIU were higher than the values that exert negative effects to E. siliculosus. However, as for TBA and IPU, the environmental concentrations were below the values which caused detrimental effects to E. siliculosus. Strain Es524, which originated from a Cu-polluted site in Chile, was found to exhibit greater resistance to the herbicides, with higher EC50 values recorded, compared to LIA4. To further elucidate the factors contributing to the relative tolerances of the two strains, responses associated with reactive oxygen species (ROS) were investigated. Measurements of H2O2 concentrations and lipid peroxidation showed significant differences between the strains, with increases in both parameters recorded at lower concentrations in LIA4 than Es524. Activities of antioxidant enzymes (CAT, APX and GR) were significantly (P < 0.05) greater in Es524 than LIA4, and total phenolic content and DPPH scavenging activity were also greater in the more tolerant strain. The rank order of toxicity of the three herbicides was diuron > terbuthylazine > isoproturon in both strains of E. siliculosus. In addition to exposure to individual herbicides, the interactions between binary mixtures were also investigated in both strains using physiological and biochemical biomarkers. All three ways of action (synergistic,additive and antagonistic) were exhibited through different endpoints applied in the present study. Significant differences (P < 0.05) between LIA4 and Es524 were observed for the DIU+TBA and TBA+IPU mixtures, while higher impacts were recorded in LIA4 strain compared to Es524. Further studies showed synergistic interactions were observed in Es524 for the aforementioned mixtures (DIU+TBA, TBA+IPU) on the antioxidative enzyme activities while in LIA4 different interactions were exhibited, which probably contribute to the higher tolerance of Es524 to the mixtures. The presence of TBA together with the phenylureas DIU/IPU was also observed to increase the stimulation of antioxidative enzymes (CAT, APX, GR) in both strains of E. siliculosus. This investigation provides new information on the abiotic stress metabolism in brown algae, and HPLC analysis demonstrates the important role of polyphenols in overcoming the impact of oxidative stress. In conclusion, exposure to the herbicides, singly and in mixtures, caused significant (P < 0.05) changes in the growth, photosynthetic efficiency, and ROM of both strains of E. siliculosus. Strain Es524 was found to be more tolerant than LIA4.

Made available in DSpace on 2015-08-20T17:10:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-03-04. Added 1 bitstream(s) on 2015-08-20T17:26:01Z : No. of bitstreams: 1 000844553.pdf: 649450 bytes, checksum: 76496516946dcfd86a01aa958e7ed9b6 (MD5) / Os adjuvantes são substâncias adicionadas à formulação dos defensivos agrícolas com o intuito de melhorar a eficácia desses produtos. O objetivo do presente trabalho foi avaliar a eficácia de óleos minerais como adjuvantes de herbicidas utilizados na cultura da cana-de-açúcar. O trabalho foi dividido em três experimentos com focos em controle de plantas daninhas em pré e pós-emergência e em erradicação da soqueira de cana-açúcar. O delineamento experimental utilizado nos experimentos foi o de blocos ao acaso, com vinte tratamentos e quatro repetições para cada experimento. As aplicações dos tratamentos foram realizadas com um pulverizador costal com pressão constante (mantida a CO 2 ) de 40 lb/pol 2, com volume de aplicação de 200 L/ha. Observou-se que, no trabalho de Controle de Plantas Daninhas em Pré-Emergência, os tratamentos com adjuvantes foram superiores aos tratamentos sem adjuvantes no controle das plantas daninhas que ocorreram no experimento: Ipomoea nil (corda-de- viola), Commelina benghalensis (trapoeraba) e Panicum maximum (capim-colonião) e foram seletivos à cultura da cana-de-açúcar. No trabalho de Controle de Plantas Daninhas em Pós-Emergência, os tratamentos com adjuvantes foram superiores aos tratamentos sem adjuvantes no controle das plantas daninhas I. nil, C. benghalensis, P. maximum e Bidens pilosa (picão-preto) e também foram seletivos à cultura, sendo que no quesito fitotoxicidade invisível detectada pelo aparelho fluorômetro, o adjuvante Oppa-BR-EC foi o mais seletivo à cultura em ambas as doses do herbicida Krismat. No trabalho de Erradicação da Soqueira de Cana-de-Açúcar, a adição de adjuvantes à calda herbicida, além de melhorar a eficácia dos tratamentos, acelerou o processo de morte das plantas; na menor dose do herbicida (glyphosato a 4,5 L p.c./ha) o tratamento que proporcionou o maior índice de dessecação foi com o adjuvante Oppa- BR-EC (1,00% v/v) e na maior... / Adjuvants are substances added to the formulation of crop protection products in order to improve the effectiveness of these products. The aim of this study was to evaluate the effectiveness of mineral oils as herbicide adjuvants used in the culture of cane sugar. The work was divided into three experiments focuses on weed control in pre- and post-emergence and eradication of cane sugar from the stump. The experimental design used in the experiments was randomized blocks with twenty treatments and four replications for each experiment. Applications of the treatments were performed with a knapsack sprayer, with constant pressure (maintained CO2) of 40 lb / in2, with application volume of 200 L / ha. It was observed that in the work of Weed Control in Pre-Emergency, treatments with adjuvants were higher than treatments without adjuvants in weed control that occurred in the experiment: Ipomoea nil (string-of- viola), Commelina benghalensis ( spiderwort) and Panicum maximum (guinea grass) and were selective for the cultivation of cane sugar. In the work of Weed Control in Post-Emergency, treatments with adjuvants were higher than treatments without adjuvants in the control of weeds I. nil, C. benghalensis, P. maximum and Bidens pilosa (beggartick) and were also highly selective culture, and in the question invisible phytotoxicity detected by the fluorometer apparatus, the Oppa-BR-EC adjuvant was the most selective culture at both doses of Krismat herbicide. At work Eradication of ratoon cane sugar, the addition of adjuvants to the herbicide spray, and improve the effectiveness of treatments, accelerated the death of plants; herbicide at the lowest dose (4.5 L glyphosato cp / ha) treatment resulted in the highest drying rate was with Oppa-US-EC adjuvant (1.00% v / v) and higher dose (6, 0 l / ha) all treatments were highly effective adjuvants and higher than the control without adjuvant

Orientador: Fernando Tadeu de Carvalho / Banca: Sergio Luis de Carvalho / Banca: Marco Antonio de Souza Silva / Resumo: Os adjuvantes são substâncias adicionadas à formulação dos defensivos agrícolas com o intuito de melhorar a eficácia desses produtos. O objetivo do presente trabalho foi avaliar a eficácia de óleos minerais como adjuvantes de herbicidas utilizados na cultura da cana-de-açúcar. O trabalho foi dividido em três experimentos com focos em controle de plantas daninhas em pré e pós-emergência e em erradicação da soqueira de cana-açúcar. O delineamento experimental utilizado nos experimentos foi o de blocos ao acaso, com vinte tratamentos e quatro repetições para cada experimento. As aplicações dos tratamentos foram realizadas com um pulverizador costal com pressão constante (mantida a CO 2 ) de 40 lb/pol 2, com volume de aplicação de 200 L/ha. Observou-se que, no trabalho de Controle de Plantas Daninhas em Pré-Emergência, os tratamentos com adjuvantes foram superiores aos tratamentos sem adjuvantes no controle das plantas daninhas que ocorreram no experimento: Ipomoea nil (corda-de- viola), Commelina benghalensis (trapoeraba) e Panicum maximum (capim-colonião) e foram seletivos à cultura da cana-de-açúcar. No trabalho de Controle de Plantas Daninhas em Pós-Emergência, os tratamentos com adjuvantes foram superiores aos tratamentos sem adjuvantes no controle das plantas daninhas I. nil, C. benghalensis, P. maximum e Bidens pilosa (picão-preto) e também foram seletivos à cultura, sendo que no quesito fitotoxicidade invisível detectada pelo aparelho fluorômetro, o adjuvante Oppa-BR-EC foi o mais seletivo à cultura em ambas as doses do herbicida Krismat. No trabalho de Erradicação da Soqueira de Cana-de-Açúcar, a adição de adjuvantes à calda herbicida, além de melhorar a eficácia dos tratamentos, acelerou o processo de morte das plantas; na menor dose do herbicida (glyphosato a 4,5 L p.c./ha) o tratamento que proporcionou o maior índice de dessecação foi com o adjuvante Oppa- BR-EC (1,00% v/v) e na maior... / Abstract: Adjuvants are substances added to the formulation of crop protection products in order to improve the effectiveness of these products. The aim of this study was to evaluate the effectiveness of mineral oils as herbicide adjuvants used in the culture of cane sugar. The work was divided into three experiments focuses on weed control in pre- and post-emergence and eradication of cane sugar from the stump. The experimental design used in the experiments was randomized blocks with twenty treatments and four replications for each experiment. Applications of the treatments were performed with a knapsack sprayer, with constant pressure (maintained CO2) of 40 lb / in2, with application volume of 200 L / ha. It was observed that in the work of Weed Control in Pre-Emergency, treatments with adjuvants were higher than treatments without adjuvants in weed control that occurred in the experiment: Ipomoea nil (string-of- viola), Commelina benghalensis ( spiderwort) and Panicum maximum (guinea grass) and were selective for the cultivation of cane sugar. In the work of Weed Control in Post-Emergency, treatments with adjuvants were higher than treatments without adjuvants in the control of weeds I. nil, C. benghalensis, P. maximum and Bidens pilosa (beggartick) and were also highly selective culture, and in the question invisible phytotoxicity detected by the fluorometer apparatus, the Oppa-BR-EC adjuvant was the most selective culture at both doses of Krismat herbicide. At work Eradication of ratoon cane sugar, the addition of adjuvants to the herbicide spray, and improve the effectiveness of treatments, accelerated the death of plants; herbicide at the lowest dose (4.5 L glyphosato cp / ha) treatment resulted in the highest drying rate was with Oppa-US-EC adjuvant (1.00% v / v) and higher dose (6, 0 l / ha) all treatments were highly effective adjuvants and higher than the control without adjuvant / Mestre