Cereal Crops

Page
2

Sorghum plants carry out C4 photosynthesis

This means that when carbon dioxide is absorbed into leaf cells it combines with molecules in the cells to make a molecule containing 4 carbon atoms

Slide 11

C3 and C4 photosynthesis

In temperate regions like the UK most plants are C3

This means that the first molecule made when CO2 enters the leaf cells has 3 carbon atoms

C4 photosynthesis is an advantage to plants in hot regions with high light intensity

Slide 12

Advantages of C4 photosynthesis

A different enzyme is used. C3 plants use the enzyme rubisco which is not very effective when CO2 concentrations in the leaf cells are relatively low.

C4 plants use the enzyme PEP this enzyme has a high affinity for CO2 even when concentrations are low, for example when plants close their stomata to reduce water loss

Slide 13

And finally Maize

Another C4 plant which is able to photosynthesis efficiently at high temperatures and light intensities.

Needs more water than sorghum but gives a higher yield so the preferred crop wherever there is enough rainfall