Table 1. OJIP parameters calculated from the direct fast imaging and P&P imaging measurements

Values represent medians ± se (n = 5 different plants). Asterisk signs denote significant differences between the two groups according to the Mann-Whitney test (*P < 0.05, **P < 0.01), which was done as a comparison of two methods: Direct fast imaging and P&P imaging. Parameter definitions according to Stirbet and Govindjee (2011): VI/J, relative variable fluorescence at the I/J step; Mo, approximate value of the initial slope of relative variable Chl fluorescence curve Vt; ΦPo, maximum quantum yield of primary PSII photochemistry (equals Fv/Fm); ABS/RC, absorption flux/effective antenna size of an active reaction center; TRo/RC, trapped energy flux leading to a reduction of QA; ET2o/RC, electron transport flux further than QA; DIo/RC, dissipation flux.

ParameterDirect Fast ImagingP&P Imaging
Vj0.510 ± 0.0050.46 ± 0.008**
Vi0.830 ± 0.0040.9 ± 0.01*
Mo1.400 ± 0.0281.11 ± 0.023*
ΦPo0.820 ± 0.0020.820 ± 0.002
ABS/RC3.37 ± 0.0483.000 ± 0.027*
TRo/RC2.780 ± 0.0352.450 ± 0.019*
ET2o/RC1.37 ± 0.0091.310 ± 0.023
DIo/RC0.600 ± 0.0150.530 ± 0.011*