Salinity affects plant growth and metabolites in plants, which in turn affect Cd accumulation. Cheng et al. ran a hydroponic experiment to assess the effect of NaCl on the metabolic response to Cd and Cd accumulation in the halophytic Cd-accumulator Carpobrotus rossii (Aizoaceae).
They find NaCl decreased Cd accumulation in the shoot by decreasing Cd root uptake and root-to-shoot translocation even under constant Cd2+ activity. Peptides and organic acids, particularly phytochelatins, play an important role in Cd tolerance and accumulation, but the change of those metabolites is not the reason for the decreased Cd accumulation.
Cheng, M., Wang, A., Liu, Z., Gendall, A. R., Rochfort, S., & Tang, C. (2018). Sodium chloride decreases cadmium accumulation and changes the response of metabolites to cadmium stress in the halophyte Carpobrotus rossii. Annals of Botany, 122(3), 373–385. https://doi.org/10.1093/aob/mcy077