Drought is a major constraint of agriculture development. The intergeneric somatic hybrids between Brassica napus and Sinapis alba were created by electrofusion to obtain materials with enhanced drought tolerance. The drought tolerance of B. napus cv. Yangyou 6 (Y6) and one offspring line (W146) of the somatic hybrids was evaluated by morphological observation. Physiological parameters were determined in this study. Moreover, the activities of a few antioxidant enzymes and the transcript level of the antioxidant enzyme encoding genes were analyzed by qPCR. W146 and Y6 showed apparent wilting after drought stress for 7 days. However, Y6 wilted more severely than W146. The result of the physiological analysis showed that the relative electronic conductivity and malondialdehyde content of Y6 were higher than that of W146. The relative water content, net photosynthesis rate, proline content, and the activities of superoxide dismutase (SOD) and peroxidase in W146 were higher than that in Y6 after drought stress for 12 days. The DNA and nitrotetrazolium blue chloride staining analysis revealed less accumulation of O2·− and H2O2 in W146 than that in Y6 after drought stress. Moreover, the transcript level of some antioxidant enzyme encoding genes, such as Cu/ZnSOD, MnSOD, ascorbate peroxidase, glutathione reductase, and glutathione peroxidase in W146, was higher than that in Y6 under drought stress. Results revealed that line W146 showed more drought stress tolerance than Y6 because line W146 could reduce oxidative damage by efficient antioxidant systems.
