Table I.

Chlorophyll fluorescence image analysis of PSII efficiency in 3-week-old wild-type and SBPase sense plants

Plants were grown in a controlled environment chamber under a light level of 600 μmol m−2 s−1. Fluorescence measurements were taken at an irradiance of 500 μmol m−2 s−1 after a series of fluorescence pulses as described in “Materials and Methods.” SBPase activity was determined in the newest fully expanded leaf. The values represent mean ± se for wild-type plants (n = 3) and for SBPase sense line 11 (n = 4), line 60 (n = 4), and line 30 (n = 4). Asterisks indicate that mean values are significantly different between wild-type and SBPase sense plants (*, P < 0.05; **, P < 0.01; ***, P < 0.001 ns >0.05). Fq′/Fm′, the quantum yield of PSII in the light; Fq′/Fv′, PSII efficiency factor and NPQ, which is determined from (Fm/Fm) −1. n.d., Not determined.

Plant LinePSII EfficiencyFq′/FvNPQSBPase Activity
Fq′/Fmμmol m−2 s−1
110.504*** ± 0.0020.708*** ± 0.0060.71ns ± 0.039.905 ± 0.998
300.495*** ± 0.0040.684** ± 0.0040.69ns ± 0.029.260 ± 0.468
600.482** ± 0.0040.674* ± 0.0070.74ns ± 0.02n.d.
Wild type0.460 ± 0.0030.642 ± 0.0050.68 ± 0.047.594 ± 1.000