Effects of fungal carbon dots application on growth characteristics and cadmium uptake in maize

The advancement of nanotechnology has led to the increased use of nanomaterials for the purpose of restoring contaminated soils. However, so far no research has been reported on the interactions of carbon dots with heavy metals (loid)s in phytoremediation. The purpose of this study was to investigate the effect of a new carbon dots derived from fungal exopolysaccharide (EPSs) on the growth and cadmium uptake in maize plants. This research was carried out using a completely randomized design with three replications in a greenhouse condition. Treatments included control, carbon dots (150 mg kg^-1), cadmium (50 mg kg^-1) and cadmium + carbon dots (50 mg kg^-1+150 mg kg^-1). The carbon dots synthesized by hydrothermal method from EPSs. The results showed that shoot dry weight and chlorophyll content of maize increased 9.7% and 23.2% in the presence of carbon dots, respectively. Carbon dots improved the chlorophyll content of maize by 24.3% in the cadmium treatment. Cadmium concentration increased (106%) in maize shoot but it decreased in root maize (68%). Carbon dots caused an increase of 5.7 and 6.7 times in the transfer factor and phytoremediation rate of cadmium, respectively. The presence of carbon dots triggered an increase of 77.9% and 39.9% of dissolved organic carbon in non-contaminated and cadmium-contaminated soils, respectively. Soil microbial biomass carbon increased 54.9% and 24.1% carbon dots and cadmium + carbon dots treatments, respectively. The study demonstrates the potential of fungal carbon dots for phytoremediation of heavy metal (loid)s contaminated soils. It also highlights the potential of nanotechnology in environmental remediation efforts.