Phytochrome-controlled level of growth substances in etiolated oat seedlings

Irradiation with red light of coleoptiles and leaves of etiolated oat seedlings, causing photoconversion of phytochrome mainly into Pfr, leads to the release of free auxins and free gibberellins from conjugated forms. The effect of red light is reversible by far-red light irradiation. A correlation between the photostationary state of phytochrome and endogenous abscisic acid content was not found.