LAUSR

Increasing interest on biological effects of electromagnetic radiation, particularly extremely-low-frequency electromagnetic fields (ELFEMFs) has been observed. Although harmful effects of magnetic fields in humans remain to be demonstrated, it has been proposed that oxidative stress may represent one of the causes of ELF- EMFs adverse effects. We investigated the influence of ELF-EMFs on enzyme activity in tobacco plants under oxidative stress. Nicotiana tabacum (L.) seedlings of the Xanthi variety were continuously exposed to 2.0 mT and 60 Hz frequency ELF-EMFs for 24, 48, 72, and 96 h. The biochemical endpoints measured involved leaf and root extracts ascorbate peroxidase (APX) and catalase (CAT) activities, which were increased in leaf extracts after 48, 72, and 96 h of magnetic field exposure, whereas APX and CAT activities in root extracts increased after 48 and 72 h and 48, 72, and 96 h of continuous exposure to magnetic fields. In contrast, ELF-EMF exposure for 24 h did not alter APX and CAT activities in leaf and root extracts. All treatment regimens were matched with a properly sham-exposed control. These results suggest that ELF-EMFs induce an oxidative stress, which may potentiate the oxidative defense system in tobacco plants