Energy-trapping Centres in Photosynthesis

Abstract

IN opaque specimens of packed Chlorella cells, the quantum yield of red fluorescence varies with the wave-length of the exciting light¹. From a maximum value measured at the absorption peak at wavelength 675 mµ, decreases to about 70 per cent of this value occur at shorter wave-lengths, as shown in Fig. 1. In contrast, dilute suspensions with measured true absorption give a relatively constant yield, suggesting that competitive selective scattering and re-absorption losses are largely responsible for the yield decreases observed in opaque specimens.