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Avaliação da resposta ao stresse oxidativo induzido por cádmio e cobre em plantas de tabaco transformadas e não transformadas
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Resumo(s)
The response of tobacco plants (Nicotiana tabacum L.) non-transformed (WT) and
transformed (B1F and B5H) with AtTPS1, the trehalose-6-phosphate-synthase gene from
Arabidopsis, to cadmium (50, 200 μM) and copper (100, 400 μM) was compared. Protein
content, antioxidative enzymes (CAT, POD, SOD, APX), lipid peroxidation and hydrogen
peroxide were determined in leaves.
WT showed a significant increase in malondialdehyde content both with Cd and Cu,
indicating occurrence of lipid peroxidation. B5H and B1F showed lower incidence of lipid
peroxidation. SOD activity showed no significant variation both with Cd and Cu, indicating
that superoxide formation was not induced by these heavy metals.
POD role in the scavenging of H2O2 was more relevant in WT than in B5H and B1F.CAT
seems to be more important in B5H and B1F than in WT, with higher activity compared to
WT.
APX showed a significant increase in activity levels in B5H, both with Cd and Cu, indicating
an important role in the elimination of H2O2. However, H2O2 removal by APX was not capable
of reducing H2O2 levels that remained significantly higher than the control. In conclusion, B1F
plants seem to be less affected by oxidative stress induced by Cd and Cu than B5H or WT.
Descrição
Mestrado em Engenharia do Ambiente - Instituto Superior de Agronomia
Palavras-chave
nicotiana tabacum cadmium copper oxidative stress antioxidant enzymes trehalose-6-phosphate-synthase cádmio cobre stress oxidativo enzimas antioxidantes trealose-6-fosfato-sintetase tabaco