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The contamination of orchard by cadmium (Cd) has recently increased in severity. To decrease the Cd content in fruit tree, a pot-based experiment was conducted to study the effects of intercropping with two

The selenium accumulation characteristics ofSolanum nigrumwith different ploidy were studied by the pot experiment, and the biomass, selenium content and selenium accumulation of diploid (Solanum photeinocarpum), tetraploid (Solanum photeinocarpum) and hexaploid (Solanum nigrum) plants were determined, the results showed that there was a difference between the biomass and selenium content of three kinds of ploidy plants ofS. nigrum. The biomass of various organs and shoots of hexaploidS. nigrumplants was significantly higher than that of tetraploid and diploid plants. In terms of selenium content and selenium accumulation, the hexaploid plants had the highest selenium content and selenium accumulation in stems, leaves and shoots. After comprehensive comparison, the hexaploidS. nigrumhas large biomass and strong selenium-enriching ability, so it can be used as an excellent plant material for soil selenium absorption and transformation.

To study the cadmium accumulation characteristics of Solanum nigrum with different ploidies, the biomass, cadmium content and cadmium accumulation of diploid (Solanum photeinocarpum), tetraploid (Solanum photeinocarpum) and hexaploid (Solanum nigrum) were measured by a pot experiment. The results showed that the biomass of roots, stems, leaves and shoots of S. nigrum plants with different ploidy all ranked as follows: hexaploid > tetraploid > diploid. Cadmium content and cadmium accumulation in stems, leaves and shoots of hexaploid plants were significantly higher than those in tetraploid and diploid plants, and the cadmium translocation factor and translocation accumulation factor of hexaploid were the largest, too. Therefore, hexaploid S. nigrum had a highest ability to extract and transport cadmium, which can be used as an ideal plant for remediation of cadmium-contaminated soil.

A pot experiment was conducted to study the effects of intercropping with Youngia erythrocarpa, Conyza canadens and Mazus japonicus on physiological and biochemical characteristics of hyperaccumulator Galinsoga parviflora under cadmium (Cd) stress. The results showed that intercropping with Y. erythrocarpa (GIY), C. canadens (GIC) and M. japonicus (GIM) all increased the superoxide dismutase (SOD), peroxidase (POD), peroxidase (CAT) activity and the soluble protein content of G. parviflora compared with monoculture (MG), the photosynthetic pigment (chlorophyll a, chlorophyll b, total chlorophyll, carotenoid) content and chlorophyll a/b of G. parviflora increased after intercropping, too. Among all treatments, GIC had the highest antioxidant enzyme activity, soluble protein content and photosynthetic pigment content. As for photosynthetic characteristics, GIC had the highest net photosynthetic rate (Pn), followed by GIY, GIM and MG. Compared with MG, the stomatal conductance (Gs) and transpiration rate (Tr) of GIC and GIM all increased significantly while that of GIC had no significant change, moreover, GIC had significantly lower CO2 concentration of intercellular (Ci) than other treatments, there was no significant difference in value of pressure deficit leaf (Vpdl) among all treatments. Therefore, under Cd stress, intercropping with C. canadens can improve the antioxidant enzyme activity and photosynthetic capacity of G. parviflora to the greatest extent, which was conducive to its remediation of Cd contaminated soil.