PubMed · 2026-06-22
Plants accidentally absorb toxic metals like cadmium and arsenic because those metals closely mimic essential nutrients — zinc and phosphate — and slip through the same transport channels. This review argues that metal toxicity is a whole-system failure of the plant's nutrient-balancing network, not just a transporter glitch.
Toxic metal(loid)s — cadmium/zinc, nickel/iron, and arsenic/phosphate — share such similar chemical shapes that plants cannot reliably distinguish them, leading to co-uptake through the same transporter families (ZIP, NRAMP, PHT, IRT, HMA).
Nutrient deficiency makes the problem worse: when soils are low in zinc or phosphorus, plants upregulate high-affinity transporters that pull in even more of the chemically similar toxic metals alongside the nutrients.
Metal toxicity is a network-level failure — disrupting cytosolic redox balance, triggering reactive oxygen species, rewiring gene expression, and dysregulating calcium and hormone signaling — not simply a matter of a single leaky transporter.