Senescence delay and change of antioxidant enzyme levels in Cucumis sativus L. etiolated seedlings by ELF magnetic fields

We exposed cucumber Cucumis sativus L. etiolated seedlings to a 50 Hz, 1-Ga uss magnetic field (MF) 24 h per day for 2 weeks in the dark, starting from complete divarication of cotyledons and observed quickened growth and prol onged life of EMF-exposed seedlings compared to the controls. Since this ph enomenon may be due to MF-induced delay in the senescence process which, in turn, is believed to be dependent on the potency of the seedling oxidative defense system, we assayed some related enzymes and found that the combine d action of higher levels of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) in MF-exposed seedlings may promote their survi val and delay the appearance of signs of decay. (C) 2001 Elsevier Science I reland Ltd. All rights reserved.