Figure 4. Rapid light response curves of PSII quantum yield and excitation pressure in Col-0, Ws-4 and Ler-0 accessions.
Leaves from plants grown hydroponically at an irradiance of 120 µmol photons m−2 s−1 were detached and illuminated stepwise using photosynthetically active radiation (PAR) of various intensities. Chlorophyll fluorescence was measured, and the quantum yield of PSII photochemistry Φ PSII (A) the excitation pressure 1-qP (B) were calculated. The data are plotted versus irradiance and represent means ±SD (n = 7). SD bars are shown when larger than the symbols.