A Darkroom Safelight for Research in Plant Physiology

Abstract
Green safelight filter systems consisting of green fluorescent lamps and laboratory-prepared dyed gelatin films are described. These make use of the most efficient spectral region for the dark-adapted eye and yet have minimum activity for exciting the plant photochemical reactions. A complete filter consists of 2 gelatin films containing tartrazine, pontacyl green BL and naphthol green B. The transmission of the filters may be shifted by varying the proportions of the dyes. With these filter systems it is possible to carry out manipulations of etiolated bean seedlings without any detectibl e photomorphogenic effect and of Avena seedlings without phototropic bending.