engleski

Impact of silver nanoparticles on photosynthesis in tobacco plants

Silver nanoparticles (AgNPs) are the dominating nanomaterial in various consumer products. To enhance nanoparticle useful properties, different surface coatings are used, which affect physico-chemical characteristics of AgNPs. As plants can have a significant role in accumulation and biodistribution of many environmentally released substances, they are also very likely to be influenced by AgNPs, serving as a potential pathway for transport and bioaccumulation of AgNPs into food chains. In this study we investigated the phytotoxicity of AgNO3 and three types of laboratory-synthesized AgNPs with different surface coatings [citrate, polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB)] on tobacco (Nicotiana tabacum L.), agriculturally interesting and frequently used model plant. In vitro grown 3-months old plants were treated with 25, 50, 75, 100 and 150 microM of AgNO3, AgNPs-citrate, AgNPs-PVP and AgNPs-CTAB. After seven days chlorophyll fluorescence parameters, concentration of photosynthetic pigments and Ag uptake were determined. Treatments with AgNO3 and all types of AgNPs resulted with the increased Ag uptake in the leaves. Positively charged AgNPs-CTAB lowered most parameters of chlorophyll fluorescence, while at higher concentrations decreased the concentration of photosynthetic pigments, including chlorophylls, thus indicating strong negative influence on photosynthetic apparatus. Treatments with AgNO3 and AgNPs-PVP, NPs with the low negative charge, decreased the non-photochemical quenching and negatively influenced majority of photosynthetic pigments, but only at higher concentrations. Negatively charged AgNPs-citrate exhibited the weakest impact by only increasing the non-photochemical quenching and concentration of lutein. We can conclude that the phytotoxicity of AgNPs is correlated with their surface coating and overall surface charge.

nanoparticles, silver, plants, tobacco, photosynthesis

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