RESUMO
Oxidative stress can be regarded as an imbalance between the amount of reactive oxygen species (ROS) and the ability of a biological system to eliminate the toxic species and repair the resulting damages. Since the germinating seeds and the resulted seedlings are rich in enzymes, whereas the treatment with chemicals affects much the seed germination, producing also ROS, we evaluate here the influence of 2,4-dinitrophenol (DNP) and potassium iodate (KIO3) on wheat germination (Triticum aestivum L.) and seedlings growth. Germination rate, the masses and heights of the 7 day old seedlings, as well as the activity of some enzymes involved in the oxidative stress such as peroxidase, catalase and superoxide dismutase were measured seven days after the chemical treatment. The treatment of the wheat seeds with 10-5 - 10-3 M solutions of DNP resulted in a relative concentration-dependent inhibition of the germination, with a concomitant stimulation of the weight and height of viable seedlings. The Gasparom variety treated with 10-5 M KIO3 showed a slight increase in the germination rate in comparison with the control batch. The two tested substances determined a significantly modified response of the oxidative stress enzymes, especially in the seeds treated with 10-4 and 10-3 M solutions.
