Abstract:A pot experiment was conducted to study the stress effects of different concentration levels of perchlorate (ClO-4) and hexavalent chromium (Cr6+) as well as their combination (ClO-4+Cr6+）upon the changes of chlorophyll florescence parameters, antioxidant enzyme activity, and chlorophyll and malondialdehyde (MDA) contents of leaves of rice. Results showed that an increase in ClO-4, Cr6+, and ClO-4+Cr6+concentrations decreased the chlorophyll florescence and chlorophyll contents of leaves significantly. Such a decrease was higher in the earlier than in the later growth stage of the rice. Both single treatment and combined treatment enhanced the peroxidase (POD) and catalase (CAT) activities and increased MDA contents in leaf. The activities of POD and CAT and the contents of MDA were higher for the ClO-4+Cr6+ combined treatment than for the individual ClO-4 or Cr6+ treatment. As the pollution of perchlorate and hexavalent chromium increased, the superoxide dismutase ( SOD) activity decreased in the tillering phase but increased in the heading stage. Toxicity and injury of the ClO-4+Cr6+ combined treatment were higher than that of individual ClO-4 or Cr6+ treatment. Interaction mechanism of perchlorate and chromium pollution on rice were warranted for further study.