title: High irradiance response promotion of a subsequent light induction response in Sinapis alba L.
abstract: Relative quantum responsivity curves for inhibition of hypocotyl elongation in Sinapis alba L. seedlings previously grown in white light confirm that a marked "end of day" inhibition response can be induced by a monochromatic light treatment (30 min) at the end of the light period. In dark grown seedlings, however, no growth inhibition can be induced by a 30 min monochromatic light treatment. A prerequisite for an induction response appears to be a pretreatment with continuous light. Far red light is most effective with blue and red light showing a lesser effectiveness. The light pretreatment also shows a marked fluence rate dependency with respect to its ability to allow an induction response to manifest itself. The pretreatment required shows all the characteristics of a classical "HIR" response. The appearance of the effect in plants treated with the herbicide SAN 9789 seems to exclude chlorophyll as being the photoreceptor.
authors.affiliation: Biologisches Institut II der Universität, Schänzlestraße 1, D-7800, Freiburg, Federal Republic of Germany.
authors.forename: C J
authors.initials: CJ
authors.lastname: Beggs
authors.forename: W
authors.initials: W
authors.lastname: Geile
authors.forename: M G
authors.initials: MG
authors.lastname: Holmes
authors.forename: M
authors.initials: M
authors.lastname: Jabben
authors.forename: A M
authors.initials: AM
authors.lastname: Jose
authors.forename: E
authors.initials: E
authors.lastname: Schäfer