Improving Cd-phytoremediation ability of Datura stramonium L. by Chitosan and Chitosan nanoparticles

Phytoremediation is a novel and cost-effective technology for removing contaminants from soil. This study investigated the effect of Chitosan (CS) and Chitosan nanoparticles (CSNPs) on phytoremediation ability of Datura stramonium L. for Cadmium (Cd) polluted soils. The results showed that D. stramonium is an accumulator plant for Cd, with the translocation factor (TF) of 1.12. Its accumulation ability was increased by the application of CS and CSNPs considerably. The concentration of Cd, in the soil, was decreased by increasing application of CS and CSNPs; also CSNPs were more effective in enhancing phytoremediation of Cd, in compared to CS. The application of CS and CSNPs significantly increased the bioconcentration factor (BCF) and TF. The highest BCF (1.85) and TF (1.65) were observed in the group treated by 5% CSNPs, showing the best function for phytoremediation of Cd. Increasing the uptake of Cd, after the CSNPs treatment, could be described as an effect of the small size, higher surface area and the low crystallinity of the nanoparticles. In the leaves of the plants treated with Cd + CS and Cd + CSNPs, the total protein content decreased in comparison to Cd- treated plants, that is the sign of Cd resistance in D. stramonium. Application of CS and CSNPs caused the increase in the peroxidase and polyphenol oxidase activities as compared to the group treated just by Cd. The results, therefore, demonstrated that D. stramonium could be suitable for phytoremediation of Cd-contaminated soils and application of CS and CSNPs could enhance BCF and TF.