Figure 4. The time required to reach 90% of the maximum net photosynthetic rate (T₉₀ of Pn) after the irradiation was changed from low light (100 μmol m⁻²s⁻¹) to high light (1,000 μmol m⁻² s⁻¹).

During the measurement, the adaxial (a,c,e) or abaxial surfaces (b,d,f) of Platanus orientalis L. (a,b), Melia azedarach L. (c,d) and Solanum lycopersicum L. (e,f) were irradiated by fluctuating light. The irradiation was switched between high and low light every 4 min, 2 min or 1 min. The x-axis indicates the start time of the high light period (as shown in Fig. 1b). Values are the mean (±SE), n = 5.