Could cocropping or successive cropping with Cd accumulator oilseed rape reduce Cd uptake of sensitive chinese cabbage?

Oilseed rape, a Cd accumulator, is effective in the uptake of plant available Cd from the soil. We hypothesize that the efficient removal of bioavailable Cd from soil solution by the Cd-accumulator oilseed rape (Brassica napus var. Xikou Huazi) might reduce the Cd uptake of coplanted or rotated Cd sensitive Chinese cabbage (Brassica campestris var. Zhongyou 821). Xikou Huazi and Zhongyou 821 were cocultivated in uncompartmentalized pots, or pots that were divided by plastic film or mesh barriers to limit the extent of root intermingling at a Cd concentration of 60 mg kg^-1. The shoot biomass of Xikou Huazi was significantly increased when its root were permitted to intermingle with Zhongyou 821. Cocropping of Xikou Huazi with Zhongyou 821 not only increased its biomass, but also increased the Cd uptake by Xikou Huazi when there was no barrier. The results were reversed for Cd sensitive oilseed rape (Zhongyou 821) in such a system. There was no significant difference in biomass, Cd concentration, and total Cd uptake for both the oilseed rape species under mixed-culture and monoculture, when grown in the pot with mesh and plastic film barrier. Successive cropping systems at Cd treatment concentrations of 0, 5, and 10 mg kg^-1 , showed that first cropping of Xikou Huazi had little influence on Cd uptake of successive cropping of Zhongyou 821. Cd-accumulator oilseed rape could reduce the Cd uptake of cocropped Chinese cabbage species.