Lemna minor recovery potential after short-term exposure to sulfonylurea herbicide

Abstract

We have investigated the effects of the sulfonylurea herbicide Sekator OD 375 on common duckweed (Lemna minor L.) and its potential to recover after the herbicide exposure. The plants were exposed to Sekator OD 375 for a 7-day period at the concentrations ranging from 5 to 100 µL L−1, equivalent to 0.005–0.1 of field application rate. The treated plants were transferred to clean fresh growth medium for a 7-day period to observe the plants recovery. The exposure to herbicide significantly reduced the growth rate and the biomass of common duckweeds (L. minor), lowered the content of photosynthetic pigments and induced membrane lipid peroxidation. After the transfer to fresh, clean growth media, the plants exposed to concentrations higher than 50 µL L−1 of herbicide showed no potential to recover. L. minor exposed to relatively low levels of herbicide (below 50 µL L−1) showed a potential to recover their new fronds production: the relative growth rate in the recovery phase was higher than in the exposure period. However, after the recovery phase, the final biomass of the exposed plants was below initial values. Exposure to the herbicide-induced membrane lipid peroxidation (measured as the concentration of malondialdehyde). Thus, plants failed to recover their membranes during the recovery phase and a further increase in the concentrations of malondialdehyde was observed.