Cereals: Rice, Maize, and Sorghum - Their Adaptations and Benefits, Slides of Biology

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Cereal Crops

Rice, Maize and Sorghum

Cereals- the worlds staple foods

• Cereals are all members of the grass family
• Examples include rice, wheat, maize and sorghum
• They are grown for their seeds (grains) which are high in carbohydrates and protein
• The water content of the grains is low compared to other vegetables

Rice

Rice

Grown in areas of high temperature and high humidity Small plants are planted out in flooded fields Rice can grow in normal soil Flooded fields reduce competition from weeds Nitrogen fixing bacteria live on flooded rice roots providing nitrate. This reduces need for fertiliser

Sorghum

• This is a cereal which is adapted to grow in arid (dry) regions and tolerate high temperatures and light intensities
• Uses a quarter of the water needed by rice
• Has a lower grain yield than cereals grown in areas where water is abundant but is often the only crop that will grow

Adaptions of sorghum to drought

• Extensive root system
• Thick cuticle (waxy layer covering leaves) reduces evaporation of water from leaves
• Sunken stomata reduce water loss by evaporation
• Stomata close during drought and reopen very quickly afterwards

Adaptions of sorghum to high light

intensity

• Sorghum plants carry out C 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

C3 and C4 photosynthesis

• In temperate regions like the UK most plants are C
• This means that the first molecule made

when CO 2 enters the leaf cells has 3

carbon atoms

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

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