title: A variable automatic recording device for measuring phytochrome with the Perkin-Elmer spectrophotometer model 356.
mesh_terms: D001322:Autoanalysis; D005069:Evaluation Studies as Topic; D008027:Light; D008722:Methods; D010860:Pigments, Biological / Q000032:analysis*; D010944:Plants; D013053:Spectrophotometry; D013997:Time Factors
chemical_list: D010860:Pigments, Biological