Fig. 4.

Relationship between PsbO leaf protein content and major proteins representing the key steps in photosynthesis. PsbD (PSII), PsaD (PSI), Rieske FeS (cytochrome b₆f), and AtpC (ATP synthase) were determined by Western blotting. Total Rubisco catalytic sites was determined on a different set of plants by ¹⁴C-CABP binding. The ∆A _max parameter is proportional to total photo-oxidizable P700 content per area. It is included to give physiological support to the change in PSI content indicated by PsaD. Solid lines indicate a statistically significant relationship: for PsbD the regression equation is y = 1.01x; for PsaD, y = 0.58 + 21.28; for ∆Amax, y = 0.02x + 1.94; for Rubisco, y = 0.04x + 13.64. Note that the slope of the regression line for PsaD is approximately half of that for PsbD.