A detailed analysis of phytochrome decay and dark reversion in mustard cotyledons

Summary During the first 10 min after a saturating dose of red light, 72 h dark-grown mustard cotyledons show no phytochrome decay. Within the same time interval there exists a transient form of P_fr (=P_fr^T) which is no longer photoconvertible at 0°C, but is at 25°C. This P_fr^Tconverts in the dark to P_frand P_r. These dark reversions take about 10 min. After a lag phase of 10 min the P_frdecay can be described by a single, first order kinetic curve. The time courses of these reactions are functions of the time of etiolation.Research supported by DAAD and by Deutsche Forschungsgemeinschaft (SFB 46).