Os herbicidas causam alterações reversíveis na comunidade fitoplanctônica em lavoura de arroz

Detalhes bibliográficos
Ano de defesa: 2013
Autor(a) principal: Reck, Liange
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de Santa Maria
BR
Ciências Biológicas
UFSM
Programa de Pós-Graduação em Agrobiologia
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://repositorio.ufsm.br/handle/1/4863
Resumo: Several agrochemicals are used for rice production in Brazil; depending on their persistence and toxicity, these substances may cause damage to non-target species and also contaminate water systems. Paddy rice fields are important elements of the landscape in Rio Grande do Sul, potentially helping to sustain regional biodiversity of several invertebrate and vertebrate animal species. Phytoplankton communities are primary producers and the base of most food chains, also working as biological filters in the depuration of water systems. The experiments reported here aimed to verify if the herbicide mix imazapyr+imazapic (Kifix®) and also the isolate components imazapyr and imazapic affect the composition and structure of the phytoplankton community in paddy rice fields, when directly added to the water. The experiment was carried out in the municipality of São Sepé, in the central region of Rio Grande do Sul, Brazil, in the crop year 2011/2012. A randomized block design was used in the experiment (5 x 3) with four repetitions. Principal Response Curve analyses of the data obtained demonstrated that both imazapyr and imazapic may have effects over the composition and abundance of phytoplankton in paddy rice fields. The greatest effects were found on three different taxonomical classes of organisms: Cyanophyceae (cyanobacteria), Chlamydophyceae (unicellular flagellates) and Chlorophyceae (green algae). Moreover, the experimental treatments with herbicide additions resembled the control in the last sampling date, indicating that the substances have a greater toxic effect in the first few days after addition.