X‐RAY SENSITIVITY OF PHOTOSYNTHETIC AND REPRODUCTIVE SYSTEMS IN CHLORELLA

Abstract— Some effects of X rays on the green alga Chlorella pyrenoidosa have been investigated by measurements of survival and oxygen‐evolving capability. Photosynthetic oxygen evolution at light saturation and endogenous respiration showed the same radiation sensitivity, and these two processes were about 40 times more resistant to X‐ray‐induced inactivation than survival. Responses of cells receiving doses in excess of 200krad are in agreement with the existence of two photosystems, photoreaction II being apparently more sensitive to X rays than photoreaction I.