Effect of brassinosteroids on seed germination and seedling growth of radish (Raphanus sativus L.) under arsenic toxicity stress

The effect of brassinosteroids on germination and seedling growth of radish (Raphanus sativus L.) under arsenic toxicity was investigated. Exogenous application of brassinosteroids substantially removed the inhibiting effect of arsenic toxicity on seed germination. The application of brassinosteroids removed the toxic impact of arsenic on seedling growth. The amelioration of arsenic stress by brassinosteroids found associated with increased levels of nucleic acids, soluble proteins as well as the osmoprotectant proline. Brassinosteroid feeding resulted in reduced membrane peroxidation (measured as MDA content) in seedlings challenged with elevated levels of arsenic. Further, the application of brassinosteroids to radish seedlings growing under toxic levels of arsenic was resulted in increased activity of antioxidant enzymes such as catalase, superoxide dismutase and peroxidase. The results of the study clearly demonstrated the protective role of brassinosteroids in radish seedlings against the arsenic toxicity.