Mitigating cadmium stress in Phaseolus vulgaris through nano silica-induced growth and cadmium uptake

Cadmium (Cd) is a highly toxic heavy metal element widely in the natural environment. To investigate the effect of nano silica (SiO₂ NPs) on the cadmium (Cd) accumulation in Phaseolus vulgaris, SiO₂ NPs (100 and 200 mg/L) was sprayed on the leaves of P. vulgaris, and the growth and Cd accumulation under Cd stress were assessed. SiO₂ NPs increased the biomass, photosynthetic pigment content, peroxidase (POD) activity, and Cd content of P. vulgaris under Cd stress. Compared to Cd treatment, the concentration of 200 mg/L SiO₂ NPs increased the Cd contents in roots and shoots of P. vulgaris by 4.97% and 13.34%, respectively. Furthermore, correlation, principal component, and cluster analyses revealed that the shoot Cd content had the closest relationship with the photosynthetic pigment content and root and shoot biomass. Therefore, SiO₂ NPs can mitigate Cd stress, promote the growth, and increase Cd accumulation of P. vulgaris, which is not suitable for the production of P. vulgaris in Cd contaminated areas.