Abstract: Arabidopsis was used as a model plant and the young seedling root response to Cd stress investigated. The study shows that increasing concentrations of Cd inhibits root elongation. Both the meristematic and elongation zones are severely truncated, suggesting some degree of impact on cell division and elongation. Plant roots die under Cd overdose. DAB staining analysis shows hydrogen peroxide (H₂O₂) accumulation in root tips when seedlings are treated with Cd. Furthermore, vitamin C (Vc) dramatically increases seedling tolerance to Cd treatment. Put together, the results demonstrate that Cd-inhibited root growth is likely caused by reduced meristematic and elongation cell division, mediated by ROS (reactive oxygen species) production.