C3- C4Intermediate Photosynthesis in Plants

Among higher plants, C3 species have high levels of photorespiration, which limit the rate of net carbon dioxide assimilation. C4 plants have evolved a mechanism that overcomes photorespiration. Some species have photorespiration levels intermediate to C3 and C4 species, as well as other intermediate anatomical, physiological, and biochemical characteristics. These C3-C4 intermediates provide excellent opportunities for studying how photorespiration is reduced, as well as the genetics and evolution of C4 photosynthesis. (Accepted for publication 11 April 1984)