Figure 9. PSII activity of Col-0, Ws-4 and Ler-0 accessions during growth under high-light conditions.

The plants were initially grown hydroponically for four weeks at 120 µmol photons m⁻² s⁻¹, and then transferred to 950 µmol photons m⁻² s⁻¹ (HL) for additional two weeks. PSII activity was measured via chlorophyll fluorescence. The Φ_PSII parameter in detached leaves under light (A) and the F _v/F _m parameter following 15 min of dark-adaptation (B) are plotted as a function of number of days in HL. The data are means ±SD (n = 5). SD bars are shown when larger than the symbols. (C) Appearance of plant health during growth under HL conditions. Two plants from each accession were photographed after the additional two weeks of growth under HL conditions.