Seleção de espécies com potencial para fitorremediação de solo contaminado com herbicidas inibidores da protox

• Ano de defesa: 2016
• Autor(a) principal: Alves, Carla
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Fronteira Sul; Brasil; Campus Erechim; Programa de Pós-Graduação em Ciência e Tecnologia Ambiental; UFFS
• Palavras-chave em Português: Tratamento do solo; Herbicidas; Fitorremediação; Extresse oxidativo; Contaminação do solo
• Link de acesso: https://rd.uffs.edu.br/handle/prefix/1540

The use of plant species for phytoremediation of soil contaminated with herbicides becomes an alternative that has been emphasizing to minimize the effects of the persistence of agrochemicals in the environment. The objective of this work was to evaluate the tolerance of winter and summer species to the herbicides fomesafen and sulfentrazone, for the possibility of phytoremediation of soil contaminated by these herbicides. In order to reach the proposed objectives, greenhouse experiments were conducted at the Federal University of Southern Frontier, Campus Erechim. The first experiment was carried out to evaluate the tolerance of winter species treated with four doses of the herbicides fomesafen and sulfentrazone. The design was completely randomized, with four replications. Using the species (Avena sativa, Vicia sativa, Rapanhus sativus, Lotus corniculatus, Lupinus albus) and the doses of herbicides (fomesafen - 0, 0.125, 0.25 and 0.5 kg ha -1 and sulfentrazone - 0, 0.3, 0.6 and 1.2 kg ha-1). The second experiment, whose objective was to evaluate the tolerance of summer Crotalaria juncea, Pennisetum glaucum, Mucuna puriens e Sorghum bicolor, treated with 4 doses of the herbicides fomesafen and sulfentrazone. The design was completely randomized, with four replications. With the application of herbicides (fomesafen - 0, 0.125, 0.25 and 0.5 kg ha-1 and sulfentrazone - 3, 0.6 and 1.2 kg ha-1). At 45 days for the winter species and at 30 days for the summer species, after the application of the herbicides the phytotoxicity of the plants was evaluated. Plant height, stem diameter, leaf area and shoot, dry mass were also determined. At 45 days after application of the herbicides, the effects on the physiological characteristics of the plants were evaluated in winter plants. The aerial part of plants of black oats, vetch, turnip and lupine were packed in foil and immediately frozen in liquid nitrogen. These samples were used to determine the activity of the antioxidant enzymes catalase and guaiacol, as well as the levels of lipid peroxidation of the plants submitted to the herbicides fomesafen and sulfentrazone. Soil from A.sativa, R. sativus, V.sativa, L. corniculatus, L. albus, and trials was used for sowing cucumber, a plant used as a bioindicator for the presence or absence of herbicides in the soil. Phytotoxicity caused by fomesafen and sulfentrazone were evaluated at 7, 14, 21 and 28 days after cucumber emergence. At 28 days the height, stem diameter, leaf area and dry mass were determined. The data were submitted to analysis of variance by the F test, where linear or non linear regressions were applied to evaluate the effect of herbicide doses on the species studied. The cornichão was the species less tolerant to the herbicides. A. sativa were slightly affected by the application of different doses of fomesafen, but were highly susceptible to sulfentrazone. R. sativus presented tolerance when applying the 0.25 kg ha-1 dose of fomesafen. For sulfentrazone this species showed tolerance. The most tolerant species to fomesafen and sulfentrazone, irrespective of the dose, was L. albus, so that it presents a possible alternative for the phytoremediation of soils treated with these herbicides. V. sativa and R. sativus nabo also showed potential for soil remediation, but at levels lower than L. albus. As for the results obtained when testing the summer species, it was observed that the M. puriens was tolerant to the herbicide fomesafen. Up to the recommended dose, 0.25 kg ha-1, Crotalaria juncea, Pennisetum glaucum, Mucuna puriens e Sorghum bicolor showed tolerance to fomesafen. Among the herbicides tested, sulfentrazone presented a higher toxic effect on the species, causing the death of plants even with the application of half of the doses. The herbicides fomesafen and sulfentrazone promoted changes in the balance of plants, generating oxidative stress and inducing the response of the plant's antioxidant system, mainly at 0.5 kg ha-1 of fomesafen, for V. sativa and R. sativus. At the same time, the dose of 1.2 kg ha-1 of sulfentrazone generated an increase in lipid peroxidation in V. sativa, R. sativus and L. albus. In addition, aveia preta was the species that showed the lowest changes in the antioxidant system with exposure to the herbicides fomesafen and sulfentrazone. Among the herbicides tested, sulfentrazone presented the highest injuries on cucumber. The winter species A. sativa, V. sativa, R. sativus and L. albus, and the species summer Crotalaria juncea, Pennisetum glaucum, Mucuna puriens e Sorghum bicolor, present potential for phytoremediation of soils contaminated with fomesafen and sulfentrazone.