LAUSR

Polygonum hydropiper L. and Polygonum lapathifolium L. are two of the well-known indigenous Mn-hyperaccumulators. Enterobacter sp. FM-1 is a plant growth-promoting bacterium (PGPB) that we found in our previous study. We intended to develop a novel strategy to improve Mn and Cd co-contaminated soil phytoremediation by using a Mn and Cd-resistant bacterium for soil bioaugmentation. We carried out this study to investigate the effects of different Enterobacter sp. FM-1 inoculation concentrations (0, 5.0 × 105, 1.0 × 106 and 1.4 × 106 CFU g−1 soil) on the phytoremediation of Mn and Cd by Polygonum hydropiper L. and Polygonum lapathifolium L. in two types of Mn-Cd co-contaminated soil. In both soils, inoculation with Enterobacter sp. FM-1 promoted the growth of both plants. Moreover, inoculation with Enterobacter sp. FM-1 (≥1.0 × 106 CFU g−1 soil) significantly increased soil Mn and Cd bioavailability and decreased the soil pH. Therefore, inoculation with Enterobacter sp. FM-1 (1.4 × 106 CFU g−1 soil) improved Mn and Cd accumulation in both plants. Polygonum hydropiper L. presented excellent Mn accumulation in both soils. Additionally, both plants exhibited strong translocation and excellent phytoextraction and bioaccumulation abilities for Mn and Cd. Our findings indicated that Enterobacter sp. FM-1 is a potent bioaugmentation agent that facilitates Mn and Cd phytoextraction in Polygonum hydropiper L. and Polygonum lapathifolium L.