Figure 1.

Experimental design for the analysis of high light-induced acclimation processes in tobacco chloroplast gene expression. A, Tobacco plants were grown under moderate light conditions (350 µmol m⁻² s⁻¹) for 11 d before they were shifted to high light (1,000 µmol m⁻² s⁻¹, in a similar growth chamber with identical growth parameters apart from the light intensity). A control set of plants was kept at 350 µmol m⁻² s⁻¹. The comparison of shifted and control plants for each time point intends to exclude circadian and developmental effects from the analyses. For details, see “Materials and Methods”. B, Phenotypes of shifted and control plants at the harvesting time points indicated at the bottom. Scale bars = 1 cm. Note the slightly paler leaf color after 2 d in high light. C, The aerial parts (except the cotyledons) of shifted and control plants were harvested at the indicated time points to identify short-, medium-, and long-term acclimation responses in chloroplast translation. Please note the logarithmic scale of the time axis starting at 1 min. Plants harvested immediately before the shift served as technical controls (0 min). A dashed line connects the time of the shift event with the logarithmic time axis.