[Role of phytochrome in seed germination of Nemophila insignis].

After a long exposure to far-red light (20 hrs, 715 mn) a short red irradiation does not induce germination again. After shorter exposure to far-red (10 hrs) the reversible red far-red reaction takes place. The germination in complete darkness is probably due to the presence of Pfr (1) in dry seeds.The photoinhibition of the germination by far-red light depends on the level of the photostationary state (P730/PTotal) and on the quantum flux density.