In our research, two fungicides were examined: one of them contained azoxystrobin while the other contained azoxystrobin and propiconazole. The trials were set up in a polytunnel (KITE Zrt.) and under field conditions (Látókép experimental site). We used the average dose of fungicides defined in the approval document.

The general aim of our research was to prove that the natural detoxification mechanism of the examined plants changed following the fungicide treatment, which can be proved by the change in the enzyme activity.

During the test, the following parameters were determined: the relative chlorophyll content (SPAD value), photosynthetic activation and changes in SOD (superoxide dismutase) activity in the reactive oxygen types and lipid peroxidation measurement based on the malondialdehyde quantity.

The treatment resulted in significant difference in the relative chlorophyll content under both growing conditions. The fungicide application decreased the relative chlorophyll content with 25% in the polytunnel. The examined enzymes activations changed in two contrasting ways. The treatment caused significant increase in SOD activity in the polytunnel. The SOD activity increased with 10% at the first sampling date and more than 40% at the second date, but no significant effect was detected in the case of field treatments. Fungicide treatment did not have any significant effect on the photosynthetic activity of the observed plants. Otherwise, fungicides had unfavorable effects on the relative chlorophyll content and the quantity of photosynthetic pigments that later may lead to decreased accumulation of organic material and biomass production.

Keywords: fungicide, lipid peroxidation, maize, relative chlorophyll content, superoxide dismutase