چکیده
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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 Se4þ, 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 formwere assessed by a range
of biophysicochemical tests. Altogether, the results asserted that Lemna minor was notably poisoned by
both capped Se NPs and Se4þ. 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 Se4þ. 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.
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