Figure 6.

Schematic models for the reciprocal changes in the affinity of L‐FNR for Fd and NADP(H) (A) and for the changes in the electron distribution from Fd to Fd‐dependent enzymes in chloroplasts by the redox states of NADP(H) (B). In panel A, the binding of NADP(H) leads to the conformational (interdomain interaction) changes of FNR so that the affinity for Fd is lowered, and vice versa. In panel B, photosystem and Fd‐dependent enzymes are depicted; GOGAT: glutamate synthetase; NiR: nitrite reductase; PSI: photosystem I; SiR: sulfite reductase. Possible suppression of electron transfer from Fd to FNR by NADPH (thick orange line) and by NADP+ (thin orange line) is depicted.