Hi I never saw this type of paper. Because rice has three type of SOD (Article In silico analyses of superoxide dismutases (SODs) of rice (...
) and this enzyme is related to plant stress as you already now. Usually, based on SOD activity, you can find about 6-10 SOD activity units after stress. But, again, this range can change. Below follows a paper that should be helpful.
Article Relationship of ROS accumulation and superoxide dismutase is...