engleski

Effects of isoproturon on the duckweed Lemna minor L.

Isoproturon is one of the most frequently used phenylurea herbicides in conventional agriculture production, and it is often detected in surface water samples. Several factors, such as different exposure conditions, can affect the ability of plants to respond adequately to herbicide toxicity. Consequently, the present study investigated the ecotoxicological effects of repeated pulsed isoproturon exposures (three days of herbicide treatment followed by four days of recovery) on Lemna minor L. relative to continuous exposure during 21 days. Common duckweed was treated with 50, 100, 150 and 200 µg/L of isoproturon added to the nutrient solution. Isoproturon inhibited frond multiplication rate and plant growth evident from decreased fresh and dry weight accumulation in treated plants. The slight recovery of growth rate was recorded in lower pulsed concentrations while continuous regime caused the most pronounced growth inhibition. Herbicide treatment caused a significant reduction in protein content as well as the decline of photosynthetic pigment content, which is in agreement with the mode of action of the tested herbicide. Antioxidant enzymes activities as ecotoxicological stress biomarkers, indicated that isoproturon treated plants were under oxidative stress. Investigations on the effects of multiple pulse exposure of non-target species to xenobiotics, parallel with standard toxicity tests can contribute to a more accurate environmental impact assessment.

Lemna minor ; Herbicides ; Isoproturon ; Exposure conditions ; Growth inhibition

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