Figure 4.

Increases in chlorophyll fluorescence after addition of nicotinamide adenine dinucleotide phosphate (NADPH) (0.25 mM) 30 s into the run and ferredoxin (Fd, 5 μM) 60 s into the run, under weak measuring light (1.0 μmol·m⁻²·s⁻¹) in thylakoid membranes (50 μg Chl·mL⁻¹) isolated from recently detached leaves (A and B) or leaves incubated in water for 20 h under high light intensity (1400 μmol·m⁻²·s⁻¹) at 24 °C (C and D). The leaves were detached from H. rosa-sinensis plants in control conditions and after exposure to three photoperiods (18 h, 60 μmol·m⁻²·s⁻¹) PPFD and 35 °C with reduced irrigation (water deficit). The stress photoperiods were separated by 6 h night-periods at 24 °C. Thylakoid suspensions from leaves incubated in water for 20 h were additionally incubated with antimycin A (2 μM) for 2 min prior to the measurements (E and F). The figure shows typical curves and the histograms of the means ± SE from five independent replicates.