Interactive Effects of Cadmium on Phenolic Compounds, Antioxidant Enzyme Activity and Oxidative Stress in Lupinus albus L. Grown in Vitro

Cadmium (Cd²⁺) is a toxic heavy metal that is widespread throughout the environment. It is a subject of interest to environmental scientists because of its toxicity to plants, animals, and humans. The current work aims to evaluate the effects of Cd²⁺ on the production of phenolic compounds and morphological, physiological and biochemical responses of Lupinus albus L. plants exposed to Cd²⁺ at 0, 10, 20, 50, 100, and 150 μM CdCl₂ for 7 days. Cd²⁺ induced negative effect on growth especially at the dose of 150 µM. Cd²⁺ also induced chlorosis and reduced photosynthetic activity. Besides, the metal increased the level of malondialdehyde (MDA). Under Cd²⁺ toxicity (50, 100, and 150 µM), the superoxide dismutase (SOD) and catalase (CAT) activities were increased or not significantly affected, while at 150 µM Cd²⁺ affected the activity of these enzymes. At the highest Cd²⁺ level (150 µM), proline and total polyphenol and flavonoid contents were markedly increased in leaves and roots of L. albus. Our results suggest that L. albus plants produced phenolic compounds with reducing capacity as a selective mechanism triggered by the highest activity of Cd²⁺.