Absorption spectra of phytochrome intermediates

Abstract

Native phytochrome (124kdalton) was isolated from etiolated seedlings of Avena sativa L. cv.Pirol (Baywa, Munich).From low temperature spectra (0 ° C to – 165 °C) of phytochrome samples irradiated either with red or far-red light, spectra of interm ediates were calculated. Both absorption bands of the phytochrome chromophore were reported.On the pathway Pr - pfr, native phytochrome does not forma bleached intermediate (meta-Rb) in contrast to degraded phytochrome.An additional intermediate, meta-Rc (λmax = 725 nm), is formed instead.On the reverse pathway only two intermediates were found, lumi-Fand meta-F. Oscillator strengths’ values were calculatedand interpreted in terms of chromophore conformation.A scheme of intermediates for native phytochrome is presented. © 1985, Walter de Gruyter. All rights reserved.