Figure 1.
Comparison of photosynthetic pathways. Transverse sections showing the different anatomies characteristic of the pathways and schematic descriptions of the route taken by carbon during photosynthesis. The path taken by a carbon molecule during fixation is given at the top: C6H12O6 (glucose) is used as a proxy for more complex carbohydrates; RuBP, ribulose-1,5-bisphosphate; PEP, phosphoenolpyruvate; conc., concentrated. Sections are modified from illustrations in Esau (1953); Gifford & Foster (1987), and an unaccessioned anatomical slide from the botany collections of the National Museum of Natural History. Light grey shading shows gas spaces and the icons show the different locations of carbon storage, fixation, and transport via the C3 and C4 cycles in each metabolic pathway.