Interaction of epibrassinolide and selenium ameliorates the excess copper in Brassica juncea through altered proline metabolism and antioxidants

24-Epibrassinolide (EBL) and Selenium (Se) individually confer tolerance to various abiotic stresses, but their interactive effect in the regulation of copper (Cu) homeostasis in plants exposed to toxic levels of Cu is poorly investigated. This study provides an insight into the effects of EBL (foliar) and/or Se (through sand) on Brassica juncea plants exposed to toxic levels of Cu. The combined effect of EBL and Se on compartmentalization of Cu, oxidative stress markers, photosynthetic machinery and biochemical traits in B. juncea were analyzed. Application of EBL and Se through different mode modulated the compartmentalization of Cu in different parts of plants, enhanced the photosynthetic traits, and activities of various antioxidant enzymes and proline accumulation in B. juncea under excess copper levels. These enhanced levels of antioxidant enzymes, proline (osmolyte) accumulation triggered by combination of EBL and Se could have conferred tolerance to the B. juncea plants under toxic level of copper and also maintained Cu homeostasis in various parts of plants. This study indicates that combination of EBL and Se through different mode is an operative approach for Cu detoxification in plants and could be exploited for removal of excess copper from polluted soil.