Table 1

Role of photosynthetic electron transport and H2O2 in the regulation of APX2-LUCexpression in transgenic Arabidopsis leaf tissue. Detached leaves were treated in LL with H2O (control), H2O2 (10 mM), DBMIB (12 μM ), DCMU (10 μM), or DCMU and H2O2 and exposed to EL for 1 hour (9–12). Luciferase activity was expressed as RLUs per gram of fresh weight. All parameters were measured in five different leaves obtained from three independent experiments (n = 15 ± SD). All treatments were statistically tested against the control. Levels of significance were calculated from the analysis of variance (ANOVA) data. ΦPSII, quantum yield of PS II electron transport; LL → EL, subsequent exposure to EL after LL treatments.

Treat- mentLL (up to 2 hours)LL → EL (1 hour)
ΦPSIIqpLuciferase activityΦPSIIqpLuciferase activity
H2O0.68  ±  0.030.85  ±  0.02 10 ± 10 0.16  ±  0.040.5  ±  0.056413  ±  534 
H2O2 0.78  ±  0.04* 0.9  ±  0.03** 532 ± 127* 0.34  ±  0.06* 0.74  ±  0.05* 5054  ±  623*
DBMIB0.44  ±  0.07* 0.57  ±  0.08* 3285 ± 837* 0.21  ±  0.080.97  ±  0.22* 3341  ±  1459*
DCMU0.09  ±  0.06* 0.11  ±  0.07*   27 ± 180.01  ±  0.01* 0.03  ±  0.03* 57  ±  49*
DCMU0.18  ±  0.05* 0.28  ±  0.06*   84 ± 25* 0.04  ±  0.04* 0.08  ±  0.05* 56  ±  31*
and H2O2