C3/C4 DB  

Search/Browse DB |  Project Resources |  Project Summary |  Home page

C4 physiology is a system of interrelated developmental, anatomical, cellular and biochemical traits that can significantly enhance photosynthetic efficiency, water- and nitrogen-use efficiency, and other characteristics that influence biomass or harvest yield under given environmental conditions. In C4 plants, physiology is regulated in cellular patterns in the leaf that both increase the efficiency of inputs and eliminate sources of losses and inhibitions. All existing species that are able to fix carbon dioxide through one of the variety of C4 schemes appear to rely on an enhancement of enzymatic activities and anatomical features, with an asymmetric distribution in most C4 species between leaf bundle sheath (BS) and mesophyll (M) cells. Most C4 species exhibit variations of Kranz anatomy, in which metabolically cooperating BS and M cell types form successive layers around a dense pattern of minor, intermediate, and major veins, although an intracellular compartmentalization of cooperating activities has been found in a few C4 species. This inter- or intracellular compartmentalization supports the delivery of CO2-derived carbon to RuBisco in an environment that limits competition from oxygen and the loss of fixed CO2.

copy right statement