Dichroic Orientation of Phytochrome Intermediates in the Pathway from PRto PFRas Analyzed by Double Laser Flash Irradiations in Polarotropism ofAdiantumProtonemata

摘要

The polarotropic response in protonemata of the fernAdiantumis regulated by phytochrome (Kadota et al. 1984); PRand PFRhave been shown to be dichroically oriented parallel and normal to the cell surface, respectively (Kadota et al. 1982). This change in the dichroic orientation of phytochrome during photoconversion was analyzed by a newly-built, polarization plane-rotatable double laser flash irradiator. A polarotropic response was effectively induced with a flash of polarized red (640 nm) light (6×l0−7s) having the vibration plane of the electrical vector parallel to the protonemal cell axis. When a flash of polarized far-red (710 nm) light (6×l0−7s) was given 30 sec after the red flash, the red flash-induced response was reversed by a far-red flash vibrating normal to the cell axis but not by one vibrating parallel. However, when given 2μs or 2 ms after the red flash, the polarotropic response was not reversed by a polarized far-red flash vibrating normal to the cell axis but was reversed by a parallel-vibrating flash. These results suggest that the orientation of phototransformation intermediates existing 2μs or 2 ms after a red flash is still parallel to the cell surface, and that the change in the orientation of phytochrome molecules occurs between 2 ms and 30 s after the re