Measurements of (a) F
, (b) Φ
and (c) NPQ during progression of drought. Measurements are shown for Columbia (◇), Landsberg (□) and C24 (Δ) plants; filled symbols represent controls, empty symbols represent drought-treated plants. For both control and drought-treated populations, n = 8 for each line; for clarity, only measurements from one control and one drought specimen of each line are displayed (see Additional file 1b for additional Fv/Fm data). (d) False-colour images of Fv/Fm measurements obtained from drought-affected specimens during late drought. The average Fv/Fm measurements of each plant are shown in the lower left corner of the respective images. Note that false-colour images were not generated at Fv/Fm values of < ~0.125; for details, refer to Experimental Procedures. The same individual specimens provided all the measurements presented in Figure 1a-d.