Biochemical and physiological responses in in vitro germinated seedlings of Brassica juncea exposed to metal stress

Background: Effects of cadmium (Cd) metal on growth, photosynthetic pigments, level of osmolytes and elements, and antioxidant potential of Brassica juncea seedlings were evaluated. Materials and Methods: Seeds were exposed to different concentrations of metal, i.e., 0, 0.2, 0.4, and 0.6 mM Cd. To investigate the metal influence on biochemical and physiological factors, observations were made on growth (fresh, dry weights, and percent germination), photosynthetic pigments (carotenoid and xanthophyll), osmolytes (proline and glycinebetaine), elements (carbon, hydrogen, nitrogen, and sulfur), antioxidative enzymes, antioxidants, radical scavenging activities, and polyphenols in 7-day old seedlings. Results: The findings of this study revealed that retardation was observed in fresh and dry weights and percent germination in comparison to control seedlings. A level of osmolytes and antioxidant potential of B. juncea seedlings were found to improve with Cd toxicity. Metal stress altered the level of photosynthetic pigments and ultra-performance liquid chromatography studies showed variations in the polyphenol content in comparison to untreated seedlings. Conclusion: The current investigation revealed that the treatment of Cd generated various defense responses in the seedlings of B. juncea to overcome the adverse effects of metal due to their hyperaccumulating response.