Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros











Intervalo de ano de publicação
1.
Braz. J. Biol. ; 74(3, supl.1): S108-S112, 8/2014. graf
Artigo em Inglês | VETINDEX | ID: vti-11429

RESUMO

Specimens of Pistia stratiotes were subjected to five concentrations of arsenic (As) for seven days. Growth, As absorption, malondialdehyde (MDA) content, photosynthetic pigments, enzymatic activities, amino acids content and anatomical changes were assessed. Plant arsenic accumulation increased with increasing metalloid in the solution, while growth rate and photosynthetic pigment content decreased. The MDA content increased, indicating oxidative stress. Enzymatic activity and amino acids content increased at the lower doses of As, subsequently declining in the higher concentrations. Chlorosis and necrosis were observed in the leaves. Leaves showed starch accumulation and increased thickness of the mesophyll. In the root system, there was a loss and darkening of roots. Cell layers formed at the insertion points on the root stems may have been responsible for the loss of roots. These results indicate that water lettuce shows potential for bioindication and phytoremediation of As-contaminated aquatic environments.(AU)


Espécimes de Pistia stratiotes foram submetidos a cinco concentrações de arsênio (As), durante sete dias. Crescimento, absorção de As, concentração de malondialdeído (MDA), pigmentos fotossintéticos, atividades enzimáticas, concentração de aminoácidos e alterações anatômicas foram avaliadas. O acúmulo de As pelas plantas aumentou com o incremento do metaloide na solução, enquanto que a taxa de crescimento e o teor de pigmentos fotossintéticos diminuiu. O conteúdo MDA aumentou, indicando estresse oxidativo. A atividade de enzimas antioxidantes e os teores de aminoácidos aumentaram nas doses mais baixas de As, declinando nas concentrações mais elevadas. Nas folhas foram observados clorose e necrose. As folhas apresentaram acumulação de amido e aumento da espessura do mesofilo. No sistema radicular houve perda e escurecimento das raízes. Camadas de células formadas nos pontos de inserção da raiz podem ter sido responsáveis pela queda das raízes. Estes resultados indicam que a alface da água apresenta potencial para bioindicação e fitorremediação de ambientes aquáticos contaminados com As.(AU)


Assuntos
Araceae/metabolismo , Arsênio/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Fatores de Tempo , Purificação da Água/métodos
2.
Ecotoxicol Environ Saf ; 105: 36-42, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24780231

RESUMO

The toxicity of arsenic (As) and the mechanisms of response to this pollutant were analyzed in two aquatic plant species, one sensitive and one tolerant to the pollutant, Salvinia minima and Lemna gibba, respectively. The plants, grown in nutrient solution at pH 6.5, were exposed to As concentrations of 0.0 and 1.0mgL(-1) for 3 days. Both species accumulated As in their tissues, which resulted in increases in H2O2 production. L. gibba accumulated eleven times more As than S. minima. However, L. gibba was more tolerant, as shown by the absence of cell membrane damage and, despite greater accumulation, smaller growth reduction than S. minima. Indeed, the index of tolerance to As was twenty percent higher in L. gibba than in S. minima, which most likely results from the presence of a more efficient defense system. This defense system in L. gibba is most likely based on sulfate absorption, assimilation and metabolism. L. gibba showed an increase in sulfate absorption and adenosine-5'-triphosphate (ATP) sulfurylase activity (the first enzyme of the inorganic sulfate assimilation pathway) following exposure to As. Consequently, the plant produced greater concentrations of sulfur-containing compounds that are involved in cellular detoxification, such as glutathione and non-protein thiols, and demonstrated greater enzymatic activity of γ-glutamylcysteine synthetase, glutathione S-transferase and glutathione reductase. Therefore, the plant׳s ability to increase absorption, assimilation and metabolism of sulfur are key steps for tolerance to oxidative stress triggered by metals.


Assuntos
Araceae/efeitos dos fármacos , Araceae/metabolismo , Arsênio/toxicidade , Enxofre/metabolismo , Traqueófitas/efeitos dos fármacos , Traqueófitas/metabolismo , Poluentes Químicos da Água/toxicidade , Araceae/crescimento & desenvolvimento , Clorofila/análise , Glutationa/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Compostos de Sulfidrila/análise , Traqueófitas/crescimento & desenvolvimento
3.
Braz J Biol ; 74(3 Suppl 1): S108-12, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25627371

RESUMO

Specimens of Pistia stratiotes were subjected to five concentrations of arsenic (As) for seven days. Growth, As absorption, malondialdehyde (MDA) content, photosynthetic pigments, enzymatic activities, amino acids content and anatomical changes were assessed. Plant arsenic accumulation increased with increasing metalloid in the solution, while growth rate and photosynthetic pigment content decreased. The MDA content increased, indicating oxidative stress. Enzymatic activity and amino acids content increased at the lower doses of As, subsequently declining in the higher concentrations. Chlorosis and necrosis were observed in the leaves. Leaves showed starch accumulation and increased thickness of the mesophyll. In the root system, there was a loss and darkening of roots. Cell layers formed at the insertion points on the root stems may have been responsible for the loss of roots. These results indicate that water lettuce shows potential for bioindication and phytoremediation of As-contaminated aquatic environments.


Assuntos
Araceae/metabolismo , Arsênio/metabolismo , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Fatores de Tempo , Purificação da Água/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA