Differential Action of Toxic Metal Ions on Thylakoid Membrane Lipid Peroxidation

The peroxidation of thylakoid membrane lipids is one of the major degradative processes causing drastic modification of structural and functional characteristics of the photosynthetic organell. The peroxidation process is modulated by a number of exogenous factors like light, pH, toxic metal ions etc. Three toxic metal ions namely mercury, lead and cadmium are able to modify the process of thylakoid peroxidation and lower photochemical potential. Different mechanisms have been proposed to explain differential action of these metal ions on peroxidation process. The cation induced modulation has been explained in terms of binding of the cation to thylakoid surface, generation and entry of reactive oxygen species and stacking ability of the cations