Phytochrome in the Fern, Adiantum capillus-veneris L.: Spectrophotometric Detection in Vivo and Partial Purification

Spectrophotometric studies of fern phytochrome were performedusing dark-grown leaves of Adiantum. The absorbance differencespectrum between the red- and far-red-light irradiated sampleshowed a photoreversible absorbance change in the far-red region,with a maximum located at 728–730 nm. The concentrationof phytochrome was highest at the leaf tips and decreased graduallyalong the leaf axis. As in the case of angiosperm phytochrome,the level of fern phytochrome decreased under continuous whitelight, and the level increased again when deetiolated tissuewas transferred back to the dark. When the fern tissue was exposedto a pulse of red light, the dark reversion of P_FR to P_R tookplace with almost no destruction of P_FR. Phytochrome could beextracted from light-grown young leaves of the fern with a slightlyalkaline, aqueous buffer that contained 1 M NaCl. The differencespectrum of the partially purified phytochrome from fern wassimilar to that of partially degraded phytochrome from angio-sperms.A polyclonal antibody raised against phytochrome from etiolatedrye seedlings immuno-stained (albeit weakly) a 110-kDa polypeptideafter fractionation by SDS-polyacrylamide gel electrophoresisof the preparation of fern phytochrome. The band was very probablyfern phytochrome since it emitted zinc-induced fluorescence. (Received July 12, 1990; Accepted October 5, 1990)