Salt-induced microscopic changes in chlorophyll fluorescence distribution in the thylakoid membrane.

Addition of 3 mM MgCl2 to isolated pea thylakoids suspended in a medium of low osmotic strength at room temperature induces an increase in chlorophyll fluorescence similar to that observed with unswollen thylakoids. Fluorescence microscopy indicates that the MgCl2 induced increase in the emission intensity involves the formation of highly fluorescent patches on the swollen vesicles. The data seems to give additional support ton the concept that salt induced chlorophyll fluorescence changes involves the lateral movement of pigment-proteins within the thylakoid membrane in such a way as to form discrete domains.