The effect of paraquat on flax cotyledon leaves: Physiological and biochemical changes.

Some of the physiological and biochemical changes which were found to occur during paraquat (1,1'-dimethyl-4,4'-bipyridylium ion) treatment of cotyledon leaves of Linium usitatissimum, are reported. Results showed an inhibition of photosynthetic CO2 uptake and electron flow of isolated chloroplasts. An increase in membrane permeability, changes in the level of the major lipid components and of malondialdehyde. These are correlated with ultrastructural changes and the discussion includes a proposed mode of action for the herbicides.