Bromide Tolerance in Salicornia brachiata Roxb, an Obligate Halophyte

摘要

In coastal marshy lands, halogen bromide concentration is reported to be generally higher than in the inland soils where, annual halophytic species naturally grow. The effect of bromide on plant responses is relatively less known. The objectives of this study were to assess the effect of sodium bromide (NaBr) on growth, photosynthetic pigments, tissue ions content and changes in enzymes activity in Salicornia brachiata, a salt marsh halophyte. Presence of NaBr in the root medium induced 200 percent increase in fresh mass and 30% increase in dry mass, compared to untreated control. Relative water content also increased significantly with NaBr treatment. Increase in fresh and dry mass was not associated with high photosynthetic efficiency as evidenced by decrease in photosynthetic pigments accumulation. However, inorganic ion analysis revealed that S. brachiata accumulated Na+ as a primary osmotica. The concentration of Na+ in NaBr treated plants was ∼4 fold higher than that measured in untreated controls and this was associated with significant reduction in K+, Ca2+, Mg2+ contents. Bromide content also increased significantly and accounted for 20 to 50 percent of dry weight. In addition, significant differences in the activities of superoxide dismutase (SOD), peroxidase (POX), catalase (CAT) and ATPase were observed in bromide treated plants. For the first time bromide tolerance in coastal halophyte was reported and the results suggest that bromide was not toxic to S. brachiata for growth and metabolism even at 600 mM. concentration and suggest that the species can be used in phytoremediation of bromide contaminated soils.