Morphological and Biochemical Responses of Spirogyra setiformis Exposed to Cadmium

This study was designed to explore the effect of exogenously applied cadmium (Cd2+) on the biochemical and morphological structure of Spirogyra setiformis. The presence of regular spiral chloroplasts at control group (without Cd2+) was deteriorated within the 30 mg/L Cd2+ group. Lower Cd2+ concentrations decreased the biomass, pigments, and protein production of the alga. Production of malondialdehyde (MDA), proline, H2O2, and total phenolic compounds increased due to the inactivation of some enzymes under Cd2+ stress. The effect of Cd2+ on the biochemical content of S. setiformis was evaluated by the canonical correspondence analysis. FTIR-ATR was used for searching active groups on the algal biomass with/without Cd2+ exposure. The results confirmed that amino, amide, and anionic groups could play a significant role on the uptake of Cd2+ by the alga. MDA, proline, H2O2, and total phenolic compounds in the alga with exposure to Cd2+ seemed to be parameters as biomarkers for metal-induced oxidative stress.