Photosynthetic carbon partitioning: its regulation and possibilities for manipulation


M. Stitt (corresponding author)


The regulation of photosynthetic sucrose synthesis and partitioning is reviewed with particular emphasis on the role of fructose-2,6-bisphosphate and sucrose phosphate synthase. It is concluded that a hierachy of regulatory mechanisms exist, which allows partitioning to be changed without this necessarily leading to a reduction in the rate of photosynthesis. Nevertheless, experimental conditions can be defined in which photosynthesis is limited by the rate of end-product synthesis. These systems can be used to screen for genetic mutants or specific inhibitors, and to investigate a shift in sink demand or environmental factors that specifically act on carbon partitioning and/or the rate of endproduct synthesis.