In mustard (Sinapis alba L.) cotyledons appearance of ‘potential capacity’ to phosphorylate is controlled by phytochrome (Pfr) through a threshold, all‐or‐none reaction. Phytochrome operates only if the hypocotyl hook is connected to the cotyledons for at least 2.5 min after the end of a 1 min inductive light pulse. Partial irradiations of hook and cotyledons show that in the case of induction of ‘potential capacity’ rapid transmission of the Pfr signal occurs from the hypocotyl hook to the cotyledons. Phytochrome within the cotyledons is totally ineffective in this regard. A 3 min red light pulse suffices for full transmission of the signal. It seems that an explanation of the facts we have observed requires a revision of the present views about communication between the organs of a plant.
No takes yet. Share an insight, caveat, or question.
Oelze‐Karow et al. (1988) studied this question.
Synapse has enriched 3 closely related papers on similar clinical questions. Consider them for comparative context: