Basic 6 · Science · Living and Non-Living Things
Adventitious and Specialised Roots
In this topic you will classify plants with adventitious and specialised roots, such as storage, prop, stilt, climbing, aerial and buttress roots.
By the end of these notes you should be able to:
- Explain what adventitious roots are
- Describe the types of specialised roots and their functions
- Classify plants according to their specialised roots
What you already know
- Tap roots and fibrous roots
Copy everything that has a blue line on its left into your notebook. The other parts are for reading.
- Strand
- Diversity Of Matter
- Sub-strand
- Living and Non-Living Things
- Indicator
- B6.1.1.1.1 – Classify plants based on their root system
Introduction
Some roots do more than anchor and absorb. Cassava roots store food, maize roots prop up the stem and huge silk cotton trees have giant roots like walls. These are specialised roots.
1. Adventitious Roots
Adventitious roots: Roots that grow from parts of the plant other than the radicle, such as the stem or leaves.
When you plant a cassava stem cutting, roots grow from the stem. These are adventitious roots. Fibrous roots of maize and grass are also adventitious because they grow from the base of the stem.
2. Types of Specialised Roots
| Type | Description | Function | Examples |
|---|---|---|---|
| storage roots | swollen roots full of starch | store food | cassava, carrot, sweet potato |
| prop (brace) roots | grow from the lower stem into the soil | extra support | maize, sorghum |
| stilt roots | grow from the stem into mud or water | support in soft ground | mangrove, screw pine |
| climbing roots | grow from the stem and cling to supports | help the plant climb | black pepper vine, money plant |
| aerial roots | hang in the air | absorb moisture from the air | orchids, some fig trees |
| buttress roots | wide, flat roots at the base of the trunk | support very tall trees | silk cotton (ceiba) tree, odum |
| breathing roots | grow upward out of mud | take in air in waterlogged soil | mangrove (pneumatophores) |
3. Why Plants Have Specialised Roots
Specialised roots help plants survive in their habitats. Tall forest trees in shallow soil need buttress roots to avoid falling in storms. Mangroves along the coast at places such as Ada and Keta live in salty, muddy water, so they have stilt roots for support and breathing roots that stick out of the mud to take in air. Cassava stores starch in its roots to survive the dry season, which is why cassava is such an important food crop.
4. Classifying Roots
| Plant | Root system | Special type |
|---|---|---|
| cassava | adventitious | storage |
| carrot | tap | storage (swollen tap root) |
| maize | fibrous | prop roots |
| mangrove | adventitious | stilt and breathing roots |
| silk cotton tree | tap | buttress roots |
Remember: A carrot is a swollen tap root. Cassava's storage roots grow from the stem cutting, so they are adventitious.
New words
- adventitious root
- A root that grows from the stem or leaf.
- storage root
- A swollen root that stores food.
- prop root
- A root that grows from the stem to give support.
- buttress root
- A flat, wide root that supports a tall tree.
- aerial root
- A root that grows in the air.
- habitat
- The natural home of a plant or animal.
Summary
- Adventitious roots grow from the stem or other parts, not the radicle.
- Specialised roots store food, support, help climbing or absorb air.
- Storage roots: cassava, carrot. Prop roots: maize. Buttress roots: silk cotton.
- Specialised roots help plants survive in their habitats.
Class activity: Root Gallery
- Collect pictures or real samples of cassava, carrot, maize prop roots and other roots.
- Label each with its type and function.
- Display them as a class gallery.
You need: Uprooted bean, Grass plants, Cassava cutting, Hand lens
Exercises
Answer in your exercise book first, then check your answers.
1. Which plant has storage roots?
- A. Cassava
- B. Maize
- C. Grass
- D. Mango
Show answer
Answer: CassavaStarch is stored.2. Maize uses which roots for extra support?
- A. Prop roots
- B. Buttress roots
- C. Aerial roots
- D. Breathing roots
Show answer
Answer: Prop rootsThey grow from the lower stem.3. Buttress roots are found in…
- A. the silk cotton tree
- B. onion
- C. rice
- D. groundnut
Show answer
Answer: the silk cotton treeThey support tall trees.4. A carrot is a swollen tap root.
- A. True
- B. False
Show answer
Answer: TrueIt stores food.5. Adventitious roots grow from the radicle.
- A. True
- B. False
Show answer
Answer: FalseThey grow from other parts.6. Roots that grow upward out of mud to take in air are ______ roots.
Show answer
Answer: breathingPneumatophores.7. Name two types of specialised roots and their functions.
Show answer
Answer: Storage roots store food; prop roots give support (or buttress, climbing, aerial).Any two.8. Explain why mangroves have stilt and breathing roots.
Show answer
Answer: They grow in soft, salty mud with little air; stilt roots support them and breathing roots take in air.Adaptation to habitat.
Homework
- Find three plants with specialised roots in your community and describe them.