Infographic Plants

Young, Sophie // Turbo-charging photosynthesis


C4 photosynthesis is a ‘turbo-charged’ form of photosynthesis found in our most productive crop species. This infographic explains how C4 photosynthesis works, what plants use it, and why it’s important to scientists, in a way that is accessible to A-Level Biology students.


C4 is a turbo-charged form of photosynthesis.

C4 photosynthesis is found in some of our most productive crop species. It is known as a ‘carbon-concentrating mechanism’ as it shuttles carbon dioxide through the cells of the leaf to concentrate it around Rubisco, the central enzyme of photosynthesis.

What is photorespiration, and why is it a problem?

Photorespiration happens when Rubisco is exposed to oxygen as well as carbon dioxide, and reacts with the oxygen instead of the carbon dioxide. This results in photorespiration instead of photosynthesis, and so the efficiency of photosynthesis is reduced. This is socio-economically costly, as it reduces crop yields.

Where are C4 plants found?

C4 grasses and shrubs are widespread in hot areas of the world, but C4 trees are rare. We do not currently know why C4 photosynthesis is so rare in trees.

Why do we care about C4 photosynthesis?

Engineering C4 photosynthesis into non-C4 crops such as rice could boost yields by up to 50%. Furthermore, the lower water and nitrogen requirements of C4 crops, and their ability to grow at hotter temperatures means C4 could act as future-proofing against climate change and fertilizer shortages. Finally, the distribution of C4 plants across the globe, as grasslands but not forests, has shaped the evolution of species, such as humans, which evolved on open grassland.

Read Sophie’s article in The Biologist: The Fab C4

Sophie Young

Sophie Young

Sophie is an ENVISION-funded PhD student at Lancaster University studying photosynthetic diversity in trees.

Sophie’s Envision profile


Twitter: @jeunesophie

Organisation: Lancaster University