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.