Anatomia e micromorfologia de Salvinia auriculata Aubl. (Salviniaceae) submetida ao arsênio

• Ano de defesa: 2012
• Autor(a) principal: Oliveira, Maria Angélica Guerra de
• Orientador(a): Araújo, João Marcos de
• Banca de defesa: Silva, Luzimar Campos da , Ribeiro, Cleberson
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Biologia Celular e Estrutural
• Departamento: Análises quantitativas e moleculares do Genoma; Biologia das células e dos tecidos
• País: BR
• Palavras-chave em Português: Salvinia; Arsênio; Morfologia
• Palavras-chave em Inglês: Salvinia; Arsenic; Morphology
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL
• Link de acesso: http://locus.ufv.br/handle/123456789/2345

Environmental contamination is a serious problem worldwide. Arsenic (As) is a metalloid that has received great attention from researchers due to its high toxicity to live beings. In this context, the use of plants has proven to be an appropriate methodology and cost-effective for the detection of pollutants. However, the use of plant species as bioindicators requires prior knowledge of their characteristics. This study aims to evaluate the responses of Salvinia auriculata Aubl. in the presence of arsenic, determining the content of this element accumulated by species and the possible effects on development, biomass accumulation, morphological alterations and anatomical structure of its leaves. The experimental design was completely randomized with control and four concentrations of As, in the form of sodium arsenate, being 0.5, 1.0, 1.5 and 2.0 mg L-1 with five repetitions, cultivated in Clark nutrient solution during 15 days in the greenhouse. Samples were analyzed by atomic absorption spectrophotometry with hydride generation, to determine the levels of As. Samples of submerged and floating leaves of the first and fourth nodes were collected and processed for microscopic analysis. Aerial parts of the plant was visibly affected, with necrotic areas on the leaf surface, with rounded shape and dark brown tint, whose intensity was directly proportional to the concentration of As. Modified leaf presented gelatinous and browning appearance. Clonal growth rates decreased strongly with increasing concentration of arsenic in the nutrient solution, with a 56.4% reduction in the concentration 0.5 mg L-1, reaching 86.7% at 2.0 mg L- 1. In relation to the accumulation, the absorption of arsenic by plants increased proportionally with the concentration of metal in solution. The microscopic analysis was able to see more dramatic damage in the first node, compared to the fourth node. In the first node may be observed accumulation of cells with content intensely colored by toluidine blue, deformation in the architecture of the epidermal cells, partial damage to trichomes, distortion of the boundary wall of xylem elements. In the fourth node occurred accumulation of contents , changes in the chloroplasts, compression of the gaps, changes in the pattern of development of trichomes with little development and reduction in thickness of the mesophyll. The anatomical changes in leaves and immersed in modified leaves of S. auriculata were evident and can be used for diagnosing injuries and for understanding the mechanisms of phytotoxicity by As.