Paired phase contrast (left) and fluorescence (right) micrographs of dark-grown pea epicotyl tissue

upper picture set: The epidermal cells appear darkcompared with the brightly fluorescent cortical cells after treatment with fluorescent anti phytochrome antibodies.
lower picture set: Bright phytochrome-associated fluorescence in guard cells
(M. J. SAUNDERS, M.-M. CORDONNIER, B. A. PALEWITZ, L. H. PRATT, 1983).