Is qE always the major component of non-photochemical quenching?

Non-photochemical quenching (NPQ) was measured in Col-0 and npq1 mutant plants of Arabidopsis thaliana exposed for 40 min to different light intensities (85, 175, 420, 750 and 1,200 μmol photons m−2 s−1). A light-induced increase of NPQ was measured in Col-0 as well as in npq1 plants but no significant differences were found between two genotypes. The three mechanisms of quenching (qE, qT and qI) were determined by the analysis of the dark relaxation kinetics of NPQ. In most environmental conditions of this work, qE was not the major component of NPQ except in Col-0 plants at 1,200 μmol photons m−2 s−1. At low light intensities qT was the sole component of NPQ and it increased as absolute value at higher irradiances in both genotypes.