Effects of intercropping with three ploidies of hyperaccumulator Solanum species on the growth and cadmium uptake of Cyphomandra betacea seedlings

To investigate the effects of intercropping with hyperaccumulator on cadmium (Cd) accumulation of non-hyperaccumulator, a pot experiment was conducted to study the effects of intercropping with three ploidies of hyperaccumulatorSolanumspecies on the growth and cadmium uptake ofCyphomandra betaceaseedlings. The hyperaccumulatorsSolanum photeinocarpum(diploid),Solanum nigrum(hexaploid), and colchicine-induced tetraploidS. photeinocarpumwere intercropped withC. betaceaseedlings under Cd-contaminated soil conditions. Intercropping with three ploidies ofSolanumspecies decreased the root, stem, leaf, and shoot biomass ofC. betaceaseedlings. Intercropping with three ploidies ofSolanumspecies also decreased the photosynthetic pigment contents (chlorophylla, chlorophyllb, total chlorophyll, and carotenoid) inC. betaceaseedlings but increased the activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) and soluble protein content ofC. betaceaseedlings. Intercropping decreased the Cd content inC. betaceaseedlings. The lowest level was observed after intercropping with the hexaploid species, while the Cd contents and extraction amount of three ploidies ofSolanumincreased by decreasing the pH of soil and increasing concentration of soil exchangeable Cd. Therefore, intercropping three ploidies ofSolanumspecies could inhibit the Cd uptake ofC. betacea, and the hexaploid (S. nigrum) was the best choice.

Automated summary

This study found that intercropping with different ploidies of Solanum species can reduce the biomass and photosynthetic pigment contents of Cyphomandra betacea seedlings, but increase the activities of antioxidant enzymes and soluble protein content. Intercropping also decreased the cadmium content in C. betacea seedlings, with the hexaploid species being the most effective choice.