Bioaccumulation of lead and oxidative stress response in Santolina chamaecyparissus

This study evaluates lead (Pb) bioaccumulation in Santolina chamaecyparissus, an aromatic plant from the Mediterranean and North Africa, known for its therapeutic uses. The research focuses on the plant response to Pb exposure, assessing oxidative stress, antioxidant enzyme activity, and the plant potential for phytoremediation. Seedlings were grown in a controlled greenhouse and exposed to treatments ranging from 0 to 2000 mg Pb kg⁻¹ of substrate for 160 days. Pb was quantified in leaves and plant substrates, and plant growth, lipid peroxidation, and the activity of antioxidant enzymes—catalase, ascorbate peroxidase, and guaiacol peroxidase—were assessed. Statistical analysis, including univariate and multivariate approaches, revealed that S. chamaecyparissus demonstrates significant tolerance to Pb, with oxidative stress and antioxidant responses only at 2000 mg Pb kg⁻¹ substrate. Lead treatment of 250 mg Pb kg⁻¹ substrate showed higher Pb accumulation factor compared to high Pb levels (500–2000 mg Pb kg⁻¹ substrate). The findings suggest the plant potential for soil decontamination and the efficacy of multivariate analysis in environmental stress research.