Action Spectrum for Photoreactivation of Ultraviolet‐induced Morphological Abnormality in Sea Urchin Eggs

An action spectrum was obtained for photoreactivation (PR) of morphological abnormality arising from ultraviolet (UV)‐irradiation of sea urchin sperm. The wavelength dependence of PR was measured by the restoration of the formation of normal pluteus larvae after the exposure of fertilized eggs to various fluences of monochromatic PR light (313 to 500 nm). The PR action spectrum showed a maximum around 365 nm and a secondary peak somewhere above 400 nm. High PR activity beyond 400 nm wavelengths may reflect an advantageous or adaptational ability to cope with harmful effects of solar UV radiation.