Soil contamination by toxic trace metal elements, like barium (Ba), may stimulate various undesirable changes in the metabolic activity of plants. The plant responses are fast and with, direct or indirect, generation of reactive oxygen species (ROS). To cope with the stress imposed by the ROS production, plants developed a dual cellular system composed of enzymatic and non-enzymatic players that convert ROS, and their by-products, into stable nontoxic molecules. To assess the Ba stress response of two
Brassicaceae species (
Brassica juncea, a glycophyte, and
Cakile maritime, a halophyte), plants were exposure to different Ba concentrations (0, 100, 200, 300 and 500 μM). The plants response was evaluated through their morphology and development, the determination of plant leaves antioxidant enzymatic activities and by the production of plants secondary metabolites. Results indicated that the two
Brassicaceae species have the ability to survive in an environment containing Ba (even at 500 μM). The biomass production of
C. maritima was slightly affected whereas an increase in biomass
B. juncea was noticed. The stress imposed by Ba activated the antioxidant defense system in the two species, noticed by the changes in the leaves activity of catalase (CAT), ascorbate peroxidase (APX) and guaicol peroxidase (GPX), and of the secondary metabolites, through the production of total phenols and flavonoids. The enzymatic response was not similar within the two plant species: CAT and APX seem to have a more important role against the oxidative stress in
C. maritima while in
B. juncea is GPX. Overall, total phenols and flavonoids production was more significant in the plants aerial part than in the roots, of the both species. Although the two
Brassicaceae species response was different, in both plants catalytic and non-catalytic transformation of ROS occurs, and both were able to overcome the Ba toxicity and prevent the cell damage.
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