Time course of changes in HO activities (U mg protein⁻¹) during transition from dark to light.

μmmol m−2s−1) or dark (D) for 5 d (25°C). Afterwards, seedlings were cultured in the Hoagland solution with or without 100 μM HO-1 inhibitor ZnPPIX treatment, in the light (L) or dark (D) for another 12 h (25°C). Before starting the experiments, 14-day-old wheat seedlings cultured in the Hoagland solution were kept in the light (L, 300 ± SE of three different experiments with at least three replicated measurements. Different letters within columns indicate significant differences (P<0.05) according to Duncan's multiple range test. Values are means