The endophytic bacterium relieved healthy risk of pakchoi intercropped with hyperaccumulator in the cadmium polluted greenhouse vegetable field

Abstract

Planting leafy vegetables, especially pakchoi, in cadmium (Cd) polluted farmland is easy to lead to excessive Cd content in edible parts, which results in high risk of food chain. In this study, a field experiment was carried out to study the effects of intercropping of pakchoi with Cd hyperaccumulator Sedum alfredii Hance, and the roles of endophytic bacterium SaMR12 was also investigated. When intercropping with Sedum, the growth of pakchoi was not affected but their Cd concentration and accumulation were significantly increased, while which were obviously decreased by SaMR12 inoculation. After intercropping, the biomass of Sedum was significantly reduced, but their Cd concentration increased. SaMR12 inoculation significantly increased Cd accumulation of Sedum, and which increased to 3 times in Sedum monoculture. Those results showed that although intercropping with hyperaccumulator could lead to higher risk of pakchoi in Cd polluted field, intercropping with SaMR12 inoculated Sedum can decrease Cd concentration of pakchoi and promote Cd absorption of Sedum, which indicated that this endophyte can be made into a microbial inoculum as a soil additive for the safe production of vegetables and the soil Cd pollution remediation.

Keywords: Brassica campestris ssp. Chinensis; Cd; Phytoremediation; SaMR12; Sedum alfredii Hance.