The Absorption of Radiation by Leaves and Algae

Progress in the quantitative study of photochemical phenomena in living organisms has long been hampered by the difficulty of making accurate determinations of the energy absorbed during irradiation. While this problem is a basic one for all photobiologists, it is only natural that it has received most attention from plant physiologists interested in the photochemistry of carbon assimilation and in the effect of light as an environmental factor. Although the following paper is mainly devoted to a discussion of the absorption of radiation by leaves, with a briefer consideration of the problems presented by algal thalli and by suspensions of unicellular forms, it will be evident that much of it is equally pertinent to absorption by animal tissues and suspensions of animal cells.