Native phytochrome (124kdalton) was isolated from etiolated seedlings o f Avena sativa L. cv. Pirol (Baywa, Munich). From low temperature spectra (0 °C to — 165°C ) o f phytochrom e samples irradiated either with red or far-red light, spectra o f intermediates were calculated. Both absorption bands o f the phytochrome chromophore were reported. On the pathway P r i V r , native phytochrome does...