Influence of Co-planting on Cd Accumulation in Oilseed Rape and Pai-tsai Plants

To study the effect of co-planting of oilseed rapes and pai-tsai on their accumulation of Cd, a pot experiment was designed by controlling the extent of rhizosphere interaction between the two plants by root barriers with plastic sheet, nylon mesh and without root barrier. The results showed that pai-tsai got the highest shoot mass under 10 mg/kg of Cd treatment when its roots were permitted to intermingle with those of Zhongyouza I. Shoot Cd concentration was significantly decreased by 64.5% compared to that of monoculture pai-tsai. However, this decrease was unconspicuous as Cd increased in the soil. Compared to the monoculture one, reduction in shoot Cd of pai-tsai in 20 mg/kg and 40 mg/kg treatments was 57.1% and 24.2%, respectively. These results indicate that Zhongyouza I could alleviate Cd toxicity to and improvement the growth conditions of pai-tsai by its strong Cd accumulation, especially in middle Cd polluted soil.