engleski

Physiological, ultrastructural and proteomic responses of tobacco seedlings exposed to silver nanoparticles and silver nitrate

The small size of nanoparticles (NPs), with dimensions between 1 and 100 nm, results in unique chemical and physical characteristics, which is why they are being implemented in various consumer products. Therefore, one of the important concerns is the potential detrimental impact of NPs on environment. As plants are the vital part of ecosystem and the first component of the food chain, the investigation of NPs phytotoxic effects is of particular interest. In this study, we investigated the potential phytotoxicity of commercial citrate-coated silver nanoparticles (AgNPs), on tobacco (Nicotiana tabacum) seedlings and compared it with the effects of the same AgNO3 concentrations. The Ag content was higher after exposure to AgNPs compared to AgNO3 of the same concentration. However, elevated ROS formation, MDA and protein carbonyl content as well as the DNA damage was recorded in AgNO3-treated seedlings, which suggests direct uptake of AgNPs by tobacco cells and high stability of applied AgNPs. Furthermore, activity of the antioxidant enzymes, particularly superoxide dismutase (SOD) and ascorbate peroxidase (APX), was in general induced in all AgNP treatments. The up-regulation of SOD and APX was additionally confirmed by proteomic analysis. This indicates that seedlings are exposed to oxidative stress, but are successfully coping with it. Moreover, ultrastructural and proteomic study revealed that photosynthesis was the biological processes on which exposure of tobacco seedlings to both types of treatments had the most significant impact, although this was more pronounced in AgNO3-treated seedlings. All these findings indicate that AgNPs can induce phytotoxic effects, but are less detrimental for tobacco seedlings compared to AgNO3.

silver nanoparticles, Nicotiana tabacum, oxidative stress, antioxidant enzymes, proteomics

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