Avaliação de técnicas de histolocalização do alumínio em folhas de espécies de Cerrado

• Autor(a) principal: Carvalho Júnior, Wellington Geraldo Oliveira
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2559
• topic: Acumuladoras de alumínio; Hematoxilina; Chrome azurol S; Accumulating aluminum; Hematoxylin; Azurol Chrome S; CNPQ::CIENCIAS BIOLOGICAS::BOTANICA

Histolocalization techniques are important tools for understanding the accumulation strategies of aluminum in plant species occurring in acid soils, a common condition in Cerrado. The objective of this work was to identify the presence of this strategy in Cerrado species, detect and quantify the sites of accumulation, testing the effectiveness of five reagents (aluminon, azurine, chrome azurol S, hematoxylin and pyrocatechol violet) and two processing techniques (without inclusion and with inclusion in methacrylate), and to evaluate the presence of aluminum at the site of accumulation of phenolic compounds. Leaf samples of nine selected species were subjected to quantification of aluminum. For anatomical study, the fragments were fixed in FAA50 and sectioned, with and without inclusion in methacrylate. The sections were submitted to reagents for detection of aluminum and phenolic compounds. Among the studied species Miconia albicans, Palicourea rigida, Qualea grandiflora, Symplocos nitens and Salvertia convallariodora can be considered as aluminum-accumulating species, with a variation in the content of the element from 1 292.0 to 4 852.4 mg.kg-1. However, there is no relation between the content of aluminum and the intensity of the response afforded by the reagents and the number of sites shown. The pectin-cellulosic walls and chloroplasts are the main sites of accumulation. Besides being more effective, hematoxylin, chrome azurol S and pyrocatechol violet provides more homogeneous results, being more suitable for use. The inclusion in methacrylate did not harm aluminum histolocalization. Among aluminum- accumulating species, only P. rigida does not present any phenolic compounds. In the other species, the sites of accumulation of phenolic compounds differ from those of aluminum, not suggesting the complexation of these substances in the studied species.