ABSTRACTThe castor bean crop plays an important social, environmental and economic role, especially due to possibility of its use as feedstock for the generation of clean energy. Thus, this study aimed to evaluate the contents of photosynthetic pigments, cell membrane extrusion and the relative water content in the leaves of the castor bean cultivar ‘BRS Energia’ under silicon and salinity levels. The experiment was carried out at Embrapa Cotton, in a completely randomized design, in a 4 x 4 factorial scheme, and the treatments consisted of four silicon levels (0, 100, 200 and 300 mg L-1) and four water salinity levels of (ECw 0, 2, 4 and 6 dS m-1), with three replicates. The gradual increase in salinity levels reduced the concentration of photosynthetic pigments, relative water content in the leaves and increased cell membrane extrusion. The increase in the concentration of silicon reduced the harmful effects of salts on the analysed variables in the castor bean ‘BRS Energia’.