Figure 1.

Changes in apparent F_o emission after a light-to-dark transition in sunflower leaves with different light-acclimation treatments. In all cases, fluorescence emission was measured from the leaves following 5 min of preillumination under 1000 μmol quanta m⁻² s⁻¹ green light. The sunflower plants had been light acclimated in a growth chamber at 650 μmol quanta m⁻² s⁻¹ PPFD for 4 h (○), light acclimated for 4 h and then treated with 10% CO for 65 s (•), or dark adapted for 10 h in the presence (▪) or absence (□) of CO.