engleski

Changes in the antioxidant status of tobacco plants upon exposure to silver nanoparticles and silver nitrate

Silver nanoparticles (AgNPs) have a wide application in consumer products due to their antimicrobial properties. However, their increasing release into water or soil represents a potential environmental hazard. In this work, in vitro grown tobacco (Nicotiana tabacum) plants were exposed to AgNPs stabilized with cetyltrimethylammonium bromide (CTAB) or polyvinylpyrrolidone (PVP) coating, and to ionic silver (AgNO3) of the same concentrations (25, 50 and 100 µM). The aim of the study was to investigate generation of reactive oxygen species (ROS) and changes in activities of antioxidant enzymes in regard to different treatments, thereby revealing if plants were exposed to oxidative stress. Silver uptake and activities of antioxidant enzymes catalase, ascorbate and pyrogallol peroxidase and superoxide dismutase were determined in leaves and roots extracts and compared to non-exposed, control plants. Obtained results showed that uptake of silver in roots after either AgNPs or AgNO3 treatment was significantly higher than in leaves, while there were no significant differences in silver uptake after AgNP- or AgNO- treatments of the same concentrations. Increase in ROS level was observed only in roots after AgNP- treatment. Significantly higher enzyme activities were observed in most treatments compared to control, although the increase was most prominent after exposure to AgNP-CTAB. To conclude, concentrations of silver as well as the form in which silver is applied seem to be correlated with changes in activities of antioxidant enzymes. Obtained results suggest that oxidative stress is associated with AgNPs toxicity in plants, and cannot be ascribed only to dissolution of silver ions.

antimicrobial agents, antioxidant status, nanosilver, phytotoxicity, silver uptake

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