Fig. 1.

Photosynthesis efficiency of photosystem II in response to an increase in growth irradiance. a Photosynthetic acclimation of photosystem II (Ф_PSII) of Arabidopsis accession Col-0. Shown are the Ф_PSII values over time (±standard error of the mean (s.e.m.); N = 3) and a chlorophyll fluorescence image of the same Col-0 plant measured 1 h after the beginning of the photoperiod, on five consecutive days. The vertical dotted line at 25 days after sowing indicates the increase in irradiance from 100 to 550 µmol m⁻² s⁻¹. b Frequency distribution of Ф_PSII measured for 344 Arabidopsis accessions at consecutive time points in the acclimation response to an increase in irradiance as shown in a, three replicate plants are measured per accession