Efeito do fósforo na captação de minerais e pigmentação de Azolla caroliniana Willd. (Azollaceae)
Carregando...
Data
2004-09-01
Autores
Adalberto, Paulo Roberto [UNESP]
Massabni, Antonio Carlos [UNESP]
Goulart, Antonio J. [UNESP]
Monti, Rubens [UNESP]
Lacava, Pedro M.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Botânica de São Paulo
Resumo
O bioacúmulo de minerais, a fixação de nitrogênio e a concentração de pigmentos em Azolla caroliniana foram estabelecidos sob estresse nutritivo. As culturas foram mantidas em frascos de poliestireno, utilizando gradiente de fosfato entre 10-7 e 10-3 mol.L-1. Os minerais (P, S, B e Sn) foram quantificados por espectrometria de emissão ótica com plasma de acoplamento induzido e o teor de nitrogênio pelo método de Kjeldahl. A atividade da nitrogenase foi determinada pela reação de redução do acetileno e as concentrações de pigmentos foram determinadas por fotometria nos extratos metanólicos acidificados. A absorção de macronutrientes (N, P, S) mostrou-se relacionada ao suprimento de fósforo, enquanto a absorção de micronutrientes (B e Sn) não sofreu este efeito. A seletividade mineral demonstra a potencialidade da A. caroliniana como biofertilizante. Para concentrações de fósforo abaixo de 10-5mol.L-1, a razão das clorofilas/antocianinas diminuiu, causando o avermelhamento do vegetal. Este comportamento de A. caroliniana poderia ser empregado para o biomonitoramento da disponibilidade de fósforo no ambiente.
Mineral bioaccumulation, N2 fixation and pigment accumulation of A. caroliniana were established under nutritional stress. Cultures were conduced in polystyrene flasks using phosphate gradient between 10-7 and 10-3mol.L-1. Minerals (P, S, B, and Sn) were quantified by induced coupled plasma and total nitrogen by Kjeldhal methodology. Nitrogenase activity was determined by the reaction of acetylene reduction and pigments were photometrically determined in acidified methanolic extracts. Macronutrients uptake (N, P, S) were shown to be related to phosphorus supplements and micronutrient absorption (B and Sn) was independent of phosphorous supplements. Mineral selectivity showed that A. caroliniana can act as biofertilizer. Phosphorus concentration below 10-5mol.L-1 decreased the ratio chlorophylls/anthocyanins causing reddening of the plant. This behaviour of A. caroliniana could be used for biomonitoring environmental phosphorus availability.
Mineral bioaccumulation, N2 fixation and pigment accumulation of A. caroliniana were established under nutritional stress. Cultures were conduced in polystyrene flasks using phosphate gradient between 10-7 and 10-3mol.L-1. Minerals (P, S, B, and Sn) were quantified by induced coupled plasma and total nitrogen by Kjeldhal methodology. Nitrogenase activity was determined by the reaction of acetylene reduction and pigments were photometrically determined in acidified methanolic extracts. Macronutrients uptake (N, P, S) were shown to be related to phosphorus supplements and micronutrient absorption (B and Sn) was independent of phosphorous supplements. Mineral selectivity showed that A. caroliniana can act as biofertilizer. Phosphorus concentration below 10-5mol.L-1 decreased the ratio chlorophylls/anthocyanins causing reddening of the plant. This behaviour of A. caroliniana could be used for biomonitoring environmental phosphorus availability.
Descrição
Palavras-chave
antocianina, Azolla caroliniana, bioacumulação de minerais, nitrogenase, anthocyanins, Azolla caroliniana, mineral bioaccumulation, nitrogenase
Como citar
Brazilian Journal of Botany. Sociedade Botânica de São Paulo, v. 27, n. 3, p. 581-585, 2004.