Figure 1.

Chlorophyll fluorescence trace illustrating the terminology and sequence of events leading to the acquisition of the raw fluorescence images from the Arabidopsis plants that are required for the construction of images of the fluorescence parameters F_v/F_m, 1–(F_o/F_p), 1–(F_o/F_i), and 1–(F_i/F_p). Plants were dark-adapted for 15 min before being exposed to weak measuring pulses for the measurement of F_o. After 20 s, a saturating pulse of approximately 4,000 μmol m^–2 s^–1 was applied for 0.8 s to allow imaging of F_m. The plants were then left in the weak measuring beam for approximately 10 min before being exposed to an actinic PPFD of 30 μmol m^–2 s^–1, and images of F_i and F_p were taken. Traces are shown for control, untreated leaves (•) and for leaves treated with 4 (□) and 8 (▴) mm Imazapyr for 24 h.