Existence of Absorption Bands at 730-740 and 750-760 Millimicrons in Algae of Different Divisions.

Absorption studies, made on suspensions of Anacystis nidulans, Chlorella pyrenoidosa, and Porphyridium cruentum by means of an integrating spectrophotometer, suggest the existence of pigments absorbing "extreme red" light in the 720- to 800-mmicro region. In the bluegreen alga Anacystis, one pigment of this type exists, which produces a relatively strong absorption band at 750 mmicro. In the green alga Chlorella and the red alga phyridium, two considerably weaker absorption bands appear, at 730 to 740 mmicro and 750 to 760 mmicro, which may be due to one or two pigments. These pigments must be responsible for the photoinhibition of photosynthesis observed in these algae in the same spectral region; as yet, no photoinhibition has been observed in Anacystis.