Fig. 4
Effect of changes in incident light intensities on the amount of ΦPSII in different maize accessions (27 DAS). a Influence of distance variation between FluorCam panels and plants on the determination of ΦPSII (n = 4–5). The values of light intensities at different distances to light sources are given in Fig. 3. Letters indicate statistically significant differences at the p < 0.05 level according to ANOVA and post-hoc Bonferroni test. b Light-response curves of apparent electron transport rates (ETR) measured with the FluorCam system for large plants. Actinic light was applied during consecutive 60 s periods with stepwise decreasing intensity. The data are the mean ± SD of 4–5 replicate measurements