Figure 3.

Immunoblot analysis of stacked spinach thylakoid membranes isolated after illumination with photosystem I-specific far-red light (>715 nm at 20°C for 130 min) in the presence of externally added photosystem I electron donors. The blot was incubated with antibodies directed against the photosystem II D1 reaction center protein. Each sample applied contained 1.0 μg of chlorophyll. 1 + 2, 0 control. 3 + 4, 130 min of illumination. 5, 130 min of illumination followed by a 90-min incubation with 0.35 mm GTP and 5 mm Mg²⁺-ions. 6 + 7, 130 min of darkness. 8, 130 min of darkness followed by a 90-min incubation with 0.35 mm GTP and 5 mm Mg²⁺-ions.