The influence of root zone environment of Suaeda heteroptera on the existence and migration of Pb

Abstract

ABSTRACT In this paper, the total metal content, exchangeable content, iron-manganese oxide-bound content, carbonate-bound content, organic sulphide-bound content, and residue-level content in the root soil of S. heteroptera under different concentrations of Pb stress were investigated. The changes of Pb in the root zone environment of S. heteroptera were studied, and its distribution characteristics, migration and transformation rules were studied, which provided a theoretical basis for the repair of heavy metal pollution by S. heteroptera. The results showed that planting S. heteroptera reduced the total amount of Pb in each soil layer in the root zone. Under Pb stress, the total heavy metal content, carbonate-bound state, organic sulphide-bound state, and residual Pb content in each layer of the root zone were directly proportional to the concentration. The organic matter sulphide-bound Pb in the surface layer, middle layer, and bottom layer of the root zone was transformed into exchangeable, carbonate-bound, Fe-Mn oxide-bound Pb, and the residual Pb content in the middle and bottom layers of the soil root zone decreased. The existence of S. heteroptera was confirmed, which increased the bioavailability of Pb, so that Pb can be easily absorbed and utilised by plants. Therefore, the cultivation of S. heteroptera has a positive impact on heavy metal pollution in the soil.