Antioxidative responses of water hyacinth under cadmium stress / Resposta antioxidativa de aguapé sob estresse por cádmio

AUTOR(ES)

Fabrício de Souza Delite

DATA DE PUBLICAÇÃO

2007

RESUMO

Plants of hyancinth were treated during 8 days in water containing 0,05 and 0,50 mM of CdCl2 under natural light in a glasshouse maintained at 25-32°C with a 16 h photoperiod. The effect of cadmium on oxidative enzymes and nitrogen metabolism was studied. After 8 days an alteration on SOD activity was observed when the pattern of bands was analyzed by electrophoresis. The activity of catalase in the leaves increased after 2 days of exposition to the metal followed by a decreasing after this period, whereas in the roots the activity was detected only in the first day being higher in the plants exposed to the metal when compared to the control. The activity of glutathione reductase decreased during the experiment, whereas the activity of glutathione S-transferase increased in the 1st and 4th days and decreased in the 2nd and 8th days. The results suggest a lipidic peroxidation in the plants exposed during four days to the highest metal concentration. When the nitrogen metabolism was concerned, the activity of nitrate reductase was shown to be changed as an effect of the metal toxicity, being predominant in the leaves in the beginning of the experiment, but in the 8th day the roots appeared to take over this function. The highest concentration of nitrate was observed in the roots, except for the plants exposed to the highest metal concentration, whereas the highest soluble amino acids concentration was observed in the leaves. Also the effect of the metal was observed on the chlorophyll content and the biomass accumulation. The highest nitrogen content was observed in the leaves showing an average of 4%, whilst the roots showed an average of 2%. According to our results the Cd inducing phytotoxicity on water hyacinth plants interfering in several physiologic processes.

ASSUNTO(S)

cadmium nitrogênio aminoácidos nitrogen estresse oxidativo water plants cádmio amino acids heavy metals plantas aquáticas metais oxidative stress

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