ABSTRACT
Thus, it was these comparisons and the C,-C4 concept that served to bring together the large body of unrelated data mentioned by Rabinowitch, 1 and synthesize a concept of the behavior of photorespiration. Furthermore, the discovery of c. photosynthesis, and the realization that photorespiration might be a serious limiting factor to growth, stimulated increasing study of the biochemical nature of the process and its subsequent linking to the metabolism of glycolate. 21 In addition, hypotheses were developed concerning the relative advantages of C 3 and c. metabolism, particularly with respect to water-use efficiency. 22 Although C 3 and c. species of the same genus can be hybridized, yielding progeny intermediate in photosynthetic behavior,Z'- 27 and although some
tropical grasses are apparently intermediate in behavior in nature, 28 · 29 it has not yet proven possible to genetically manipulate to advantage the characteristics of photorespiration in crop plants or to breed photorespiration out of C, plants.
