Figure 9.

Example of changes in quantum yield of photosystems II (Φ_PSII) and non-photochemical quenching of chlorophyll fluorescence (NPQ) after injection of sodium orthovanadate (OV) (a) and average magnitudes of these changes (b) in protoplasts of peas (n = 6). OV was dissolved in standard solution (1 mM KCl, 0.5 mM CaCl₂, and 0.1 mM NaCl); the arrows mark the OV injection into the protoplast incubation medium (injection volume was 30 µL and final OV concentration was 0.25 mM). The incubation medium for protoplasts included sorbitol (400 mM), CaCl₂ (5 mM), MgCl₂·6H₂O (5 mM), NaCl (20 mM), and MES-KOH (30 mM). The pH was about 5.5. The final volume (the incubation medium + protoplasts) was about 3 mL. Photosynthetic measurements were recorded under blue actinic light (460 nm, 108 µmol m⁻² s⁻¹). *, the average change was significant (p < 0.05).