Phytochrome and Seed Germination. IV. Action of Light Sources With Different Spectral Energy Distribution on the Germination of Tomato Seeds.

Germination of tomato seeds exposed to a single, saturating irradiation from light sources of different spectral energy distribution seems to be dependent upon the photostationary P(FR)/P(R) ratio established by the irradiation. Germination of tomato seeds exposed to prolonged irradiations from the same light sources does not seem to be controlled solely by the P(FR)/P(R) ratio induced and maintained by the irradiation.