Heavy metals are emerging environmental contaminants. Accumulation of heavy metals beyond critical levels produces oxidative stress in plants. This stress is usually conquered by antioxidant defence system and compatible solutes. Thus, the present study has been focused to analyze the effect of Cd metal on level of elements (carbon, hydrogen, nitrogen and sulfur) & osmolytes (proline and glycine-betaine), antioxidant assays (ferric ion reducing antioxidant power and molybdate ion reduction assay), antioxidative enzyme activities (GPOX, GST, DHAR, MDHAR and PPO), photosynthetic pigments (anthocyanin and xanthophyll) and gaseous exchange parameters (transpiration rate, vapour pressure deficit and intrinsic mesophyll rate). Seeds of Brassica juncea var. RLC-1were given Cd metal (0, 0.2, 0.4 and 0.6mM) treatment. Toxic effects of Cd were observed in terms of inhibition of transpiration rate, vapour pressure deficit and intrinsic mesophyll rate, whereas improved level of compatible solutes and antioxidant potential of Brassica juncea plants helped in overcoming the adverse effects of metal.