Bundle Sheath Cells

Bundle sheath cells are specialized cells found in C 4 plants that lie below a layer of mesophyll cells (Figure 17.25). The bundle sheath cells are the sites within C 4 plants where the Calvin cycle enzymes are located. By being beneath the mesophyll cells, the bundle sheath cells have a lower oxygen concentration and a steady supply of CO 2 from the mesophyll cells (Figure 17.26). The combination of these factors helps reduce the amount of wasteful oxgenase activity of rubisco, known as photorespiration.

See also: The C 4 Cycle, Photorespiration,