title: Immediate phytochrome action in lettuce seeds and its interaction with gibberellins and other germination promoters.
abstract: An immediate action of phytochrome (PFR) was found by a technique of adding subthreshold concentrations of gibberellic acid (GA3) after irradiation. It was shown that phytochrome (PFR) is active within 5 mins after its formation. The interaction between PFR, GA3 and six other gibberellins (GA1, GA4, GA5, GA7, GA9 and GA13) was synergistic. This result is interpreted to mean that PFR does not produce any of these gibberellins, at least during the first 30 mins. of its action. This conclusion was confirmed by interaction experiments in darkness using GA3 combined with the other gibberellins. A similar synergism was found between PFR and kinetin, thiourea and chloramphenicol.
authors: Department of Biology, Queen Elizabeth College, University of London, W. 8, London.
authors: J D
authors: JD
authors: Bewley
authors: M
authors: M
authors: Negbi
authors: M
authors: M
authors: Black