Low-temperature studies on phytochrome: light and dark reactions in the red to far-red transformation and new intermediate forms of phytochrome.

The existence of a number of transient intermediates in the interconversion of he red (Pr) and far-red (Pfr) forms of phytochrome has been demonstrated in this laboratory by flash-excitation technique.' stages of the reaction the first photoproduct Pr, stabi-lized, is photoconvertible back to Pr. phytochrome.