Toxicological implications of selenium nanoparticles with different coatings along with Se4+ on Lemna minor

•Comprehensive investigation of the uptake of nanoparticles by an aquatic plant and their bioaccumulation in Lemna minor.•Synthesis of selenium nanoparticles with different surfactants and study of their influence on different physiological parameters compared to the Se4+ ions.•Evaluation of toxicity both from microscopic view and cellular activities concerning the plant defense system.

Nanoparticles have potential high risks for living organisms in the environment due to their specific qualities and their easy access. In the present study, selenium nanoparticles (Se NPs) with two different coatings (l-cysteine and tannic acid) were synthesized. The characteristics of particles were analyzed using XRD, FT-IR and SEM. The impact of the nanoparticles besides Se4+, on the aquatic higher plant Lemna minor was evaluated and compared. Entrance of l-cysteine and tannic acid capped Se NPs in the roots of Lemna minor was proved by TEM and fluorescence microscopy. Adverse effects of mentioned NPs and differences of these effects from those by sodium selenite as the ionic form were assessed by a range of biophysicochemical tests. Altogether, the results asserted that Lemna minor was notably poisoned by both capped Se NPs and Se4+. Thus, growth and photosynthetic pigments were decreased while lipid peroxidation along with total phenol and flavonoid contents were raised. Eventually some changes in enzymatic activities were presented. To sum up the consequences, it can be concluded that all changes occurred due to the plant defense system especially in order to remove reactive oxygen species (ROS) and possible phytotoxicity originated by l- cysteine and tannic acid capped Se NPs in addition to Se4+. The influence of tannic acid capped Se NPs after sodium selenite is stronger by the means of antioxidant enzymes activity in comparison with l-cysteine capped Se NPs.

Graphical abstractThe entrance of synthesized Se NPs (capped with l-cysteine and tannic acid) in Lemna minor demonstrating toxicity.Download high-res image (289KB)Download full-size image