Uptake of gold, silver, and copper nanoparticles by Calendula officinalis L. and their effect on the plant biochemical parameters

Abstract

The impacts of copper, gold, and silver nanoparticles on calendula (Calendula officinalis L.) and soil microbial activity were studied. The nanoparticles were introduced into soil in concentrations of 1–100 mg/L by root irrigation. Their size and shape were determined by transmission electron microscopy, while the uptake by the plant was determined by proton-induced gamma emission (PIGE) for silver and gold, and inductively coupled plasma atomic emission spectroscopy (ICP-OES) for copper. The accumulation of the gold nanoparticles in the aerial parts of calendula was 1–33 mg/kg. It was comparable to the parallel cases with the copper nanoparticles and significantly exceeded the corresponding data for the silver nanoparticles, which in the maximal cases were 3.59 ± 0.10 mg/kg in leaves and 3.96 ± 0.12 mg/kg in flowers. All nanoparticles provoked changes in the antioxidant activity in the aerial parts of the plant and significantly suppressed the soil microbiological activity. The silver nanoparticles had the greatest negative effect on the plant pigment content and on the soil respiration rate. The obtained results present interest for plant nanotoxicology.