Tolerance and trace elements extraction of Alliaria petiolata and Salix aquatica grandis under increased Cd(II) and Zn(II) exposure

The use of accumulator species with high biomass production in phytoextraction scenarios is frequently studied, particularly in combination with treatments that increase the bioavailability of trace elements (TE) such as Cd(II) and Zn(II). In this context, this study aimed to test the potential of Alliaria petiolata and Salix aquatica grandis for phytoextraction through their tolerance and accumulation capacities in hydroponic conditions under increasing concentrations of Cd(II) or Zn(II).Both species showed high tolerance to these elements, in particular, A. petiolata showed few symptoms of phytotoxicity when grown under Cd(II) exposure. In addition, high maximum concentrations were observed in the leaves of A. petiolata (Cd(II): 332.1 mg kg^-1 DW; Zn(II): 1614.8 mg kg^-1 DW) and for S. aquatica grandis (Cd(II): 129.3 mg kg^-1 DW; Zn(II): 2227.2 mg kg^-1 DW). Our finding demonstrate that the extraction of Cd(II) and Zn(II) also increased with their concentrations in nutrient solution but is ultimately constrained by species-specific toxicity thresholds, highlighting an optimal range for assisted phytoextraction. The present study highlighted the potential and limitation of both A. petiolata and S. aquatica grandis for Cd(II) and Zn(II) extraction purpose when exposed to high concentrations. Field trials with these species are the next step in confirming their potential in a complex environment with environmental issues to consider.