Physiological Behavior and Antioxidant Responses of Abelmoschus esculentus (L.) Exposed to Different Concentrations of Aluminum and Barium

Soil contamination by trace metal elements, such as aluminum and barium, presents specific environmental risks, particularly to plant health and agricultural productivity. Excessive accumulation of these toxic elements in plant tissues can alter redox equilibrium and affect homeostasis. This study sought to examine the physiological reactions of Abelmoschus esculentus (L.) under aluminum- and barium-induced stress. The plants were exposed to multiple concentrations of Al or Ba (0, 100, 200, 400 and 600 µM) for 45 days; then, the accumulation potential of Al and Ba, oxidative damage, and antioxidative metabolism were assessed. Key findings showed a proportional distribution of the Al and Ba in roots and aerial parts of the plants, with lower accumulation in the fruits. The occurrence of oxidative damage and the involvement of antioxidant enzymes were demonstrated by increased amounts of malondialdehyde and H2O2, enhanced activity of superoxide dismutase, and decreased catalase activity. The study also highlighted that GSH played a primary role in Al detoxification in the roots and fruits, while phytochelatins were more active in Ba-treated plants, particularly in roots and shoots, facilitating Ba sequestration.