Fig. 4

Measurement of the relative PSII and PSI amplitudes by 77K fluorescence spectroscopy. a The amplitude of PSII and PSI in WT during N deprivation. b The amplitude of PSII and PSI in tab2 during N deprivation. c The PSII/PSI ratio for WT and tab2 cells during the N deprivation time course. d Spectroscopic quantification of P₇₀₀ ⁺ content under N-depleted conditions in WT and tab2 cells. Data were collected after illumination in the presence of DCMU