The interactive effect of elevated CO2 (EC) and moisture stress (MS) on Brassica juncea cv. Pusa Bold was studied using open-top chambers. The EC markedly increased net photosynthetic rate and internal CO2 concentration and reduced variable and maximal chlorophyll fluorescence. Under MS, EC increased water potential and relative water content, and reduced transpiration rate. The greater allocation of biomass to the roots, which serve as a strong sink for assimilated carbon under EC, helped in better root growth. and B. K. Rabha, D. C. Uprety.