TABLE 1.

Summary of illumination programs and the corresponding physiological questions investigated by these approaches.

Abbreviation	Illumination program	Physiological state in question
Control
Dark	14 d of growth in 16 h WL/8 h dark; harvest under safe green light before beginning of next light period	State of PS at the end of a dark period in a standard dark-light growth schedule (state 1 as in Wientjes et al., 2013).
Light-quality shifts
Dark - PSII 50	14 d of growth in 16 h WL/8 h dark + 50 min PSII-light	Induction of state 2 by 50 min of PSII-light instead of WL.
Dark - PSII 50 - PSI 30	14 d of growth in 16 h WL/8 h Dark + 50 min PSII-light + 30 min PSI-light	Induction of state 1 by additional 30 min of PSI-light.
Dark-white light (WL) shifts
Dark - WL 50	14 d of growth in 16 h WL/8 h dark + 50 min WL	State of PS after 50 min of WL following the last dark period (state 2 as in Wientjes et al., 2013).
Dark - WL 50 - Dark 15	14 d of growth in 16 h WL/8 h dark + 50 min WL + 15 min dark	Effect of additional 15 min of dark after 50 min illumination (re-opening of PSII centers).
Dark - WL 2 h	14 d of growth in 16 h WL/8 h dark + 2 h WL	Approval of state 2 after extended illumination with WL.
Dark - WL 2 h - Dark 15 min	14 d of growth in 16 h WL/8 h dark + 2 h WL + 15 min dark	Effect of additional 15 min of dark after extended WL acclimation (re-opening of PSII centers).

All plants analyzed were 14 days old. For plants subjected to long-term light-quality treatments the pre-growth phase was correspondingly shortened. Abbreviations used: d, days; h, hours; min, minutes; PS, photosynthesis apparatus. Abbreviations for light sources are as given in main text.