Effects of tetraconazole on antioxidant system in Lemna minor

Tetraconazole is a triazole fungicide widely used in agricultural fields and is potentially carcinogenic to humans. Previous studies have shown that this fungicide has toxic effects on plants and other non-target organisms. In this study, the impact of tetraconazole on the antioxidant system of duckweed (Lemna minor), a macrophyte plant, was evaluated. For this purpose, duckweed was exposed to tetraconazole at different doses (0.005, 0.01 and 0.02 ppm) for 7 days and the changes in photosynthetic pigments (chlorophyll a, chlorophyll b, carotenoids), malondialdehyde (MDA) and hydrogen peroxide (H2O2) levels were determined. In addition, changes in superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) enzyme activities and expression of genes encoding these enzymes were also measured. The results showed that tetraconazole exposure decreased photosynthetic pigment levels and increased MDA and H2O2 levels. In comparison to the control groups, the activities of SOD, CAT, POD and APX enzymes increased in a dose-dependent manner. Tetraconazole exposure also induced the mRNA expression levels of SOD, CAT and POD genes in L. minor in a dose-dependent manner. These results indicated that tetraconazole induced oxidative stress and activated the antioxidant system in duckweed.