Photoassembly of apo-WOC-PSII using long laser flashes of variable length. (A) Flash sequences used in this experiment. Each flash train is comprised of 20 flashes. Each flash is comprised of a series of n shorter flashlettes (500 μs each). (B) The resulting O2 signal for the 0–50 s range. (C) Enlarged O2 signal for the 0–20 s range. Flash length in units of 500 μs (and O2 activation flash number minus the number of flashes before O2 is observed) for each trace: (a) 1 (14), (b) 2 (8), (c) 4 (6), (d) 8 (4), (e) 16 (2), (f) 32 (2), (g) 64 (2), and (h) 128 (2). Traces are scaled for clarity.