Ultrastructural observations on deep-etched thylakoids.

Deep etching of spinach thylakoids frozen in water exposes the inner and outer surfaces of the thylakoid. Both these surfaces differ greatly in appearance from their respective adjacent fracture planes. This finding constitutes further evidence for membrane splitting during the fracture process. Modification of the fracture face by loss of shattered material or by plastic deformation may explain the partial mismatch between the two fracture faces observed in washed thylakoids.