Research progress on detoxification and tolerance mechanisms of plants under cadmium stress

Focusing on plant responses to cadmium (Cd) stress, this review synthesizes an evidence-graded framework of coordinated cell wall-vacuole detoxification. The cell wall limits Cd entry through extracellular immobilization and chemical binding, whereas vacuolar chelation and compartmentalization reduce the toxicity of Cd that reaches the symplast. Across the available literature, these defenses may act sequentially, be enhanced in parallel, or share upstream signaling and transcriptional regulation. The review integrates physiological, biochemical, and molecular evidence relevant to Cd uptake, transport, sequestration, and tolerance, with particular attention to the evidentiary strength of proposed regulatory links. Current evidence more consistently supports functional complementarity and shared regulation than direct molecular coupling or supra-additive synergy. This evidence-graded perspective provides a more precise basis for interpreting plant Cd tolerance and for developing low-Cd crops and remediation strategies.