Excess light-acclimated T2 exhibits a faster rise in quantum yield of photosystem II
(ΦPSII), and/or higher maximum ΦPSII, than its
diploid progenitors under NPQ measurement conditions
(2000 μmol m−2 s−1 light
intensity, 0% CO2, 2% O2). Under the general linear
model (GLM), the main effect of light treatment had a significant effect on
ΦPSII (F1,14=287.513, P<0.001),
but species (F2,14=1.055, P=0.374), and the
interaction of treatment and species (F2,14=2.629,
P=0.107) were not significant. A single-factor analysis of variance
testing the effect of species on ΦPSII under EL did detect a significant
effect (F2,7=5.229, P=0.041). (a)
Initial rise in ΦPSII during the first minute of illumination for plants
grown under LL. (b) Initial rise in ΦPSII during the first minute
of illumination for plants grown under EL. (c) Maximum ΦPSII
achieved during NPQ measurement for plants grown under LL (D4L, D3L, T2L) and EL (D4E,
D3E, T2E). Letters above columns indicate statistical significance between samples under
the GLM—categories not sharing a letter differ significantly at P<0.05
(Tukey's HSD). White letters inside the EL columns indicate statistical
significance between species within EL based on a single-factor analysis of variance
comparing differences among species under EL (Tukey's HSD). In all the three
panels, error bars represent s.e. (N=3 (D3 and D4) or 4 (T2)).