Abstract:Metabolic changes of the activated oxygen in leaves of the "polima" rape ( Brassica napus L. ) between the cytoplasmic male sterility (CMS) line and its maintainer during various developmental stages were compared. During the vegetative developmental stage, lower efficiency of O2 formation,higher H2O2 and malondialdehyde (MDA) contents and higher activity of superoxide dismutase (SOD) were found in the CMS than in the maintainer line, but difference in peroxidase (POD) and catalase (CAT) activities were very little. During the stem elongation and flowering stages, the CMS had higher efficiency of O2- production, higher contents of H2O2 and MDA, lower activities of SOD, CAT and POD than the fertile line. It is concluded that the trend of different changes in activated oxygen metabolism may be associated with pollen abortion in rape.