LO 1.2 - Roots Flashcards
- Function: primary and secondary - True and adventitious - Tap and fibrous - Anatomy: Rootcap, epidermis, cortex and stele - Modifications: aerial, stilt and tuberous
Question
What are the Key functions of Roots?
Name 4 things.
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- Anchorage
- Absorption
- Storage
- Growth
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Question
What is Anchorage?
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Roots anchor plants firmly in the ground and provide support for vertical growth.
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Question
What is Absorption?
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Water and nutrients such as minerals are absorbed by roots and transported through the plant to the locations where they are needed.
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Question
What is Storage?
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Many plant species use roots as a storage organ, primarily for carbohydrates.
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Question
What is Growth?
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Dividing cells in the root cap are responsible for the elongation of root.
(Primary growth)
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Question
What are some secondary functions of Roots?
4 things
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- Prevent soil erosion.
- Mechanical support.
- Climbing.
- Nitrogen Fixation.
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Question
How do roots prevent soil erosion?
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Prevent soil erosion – roots help hold the soil matrix firmly.
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Question
How do roots give mechanical support?
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Mechanical support - Roots can provide stability to the plant.
Eg, In Maize and sugarcane stilt roots developed on the lower part of node which provide mechanical support to the plant.
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Question
How do roots help in climbing?
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Climbing – roots can help weak stemmed plants to cling and climb. Example Ivy
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Question
What is Adventitious Root?
Define it, remember it.
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Adventitious root
Roots that grow from the stem base / also formed on cuttings.
They do not develop from the radical of the seed.
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Question
What are Fibrous roots?
Define it, remember it.
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Fibrous roots
Are a fine network of branching roots.
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Question
What are Lateral roots?
Define it, remember it.
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Lateral roots
Grow out at right angles from parent root.
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Question
What is the Primary root?
Define it, remember it.
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Primary root
First roots that grow from the seed.
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Question
What are Root hairs?
Define it, remember it.
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Root hairs
Single celled ext of the epidermal cells, close to the growing root tip.
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Video
Root hairs in detail.
1 minute watch.
Root Hairs
* Root hairs exist so plants can take up more water/minerals .
* They consist of a nucleus, large vacuole, cytoplasm and mitochondria.
* No chloroplast – So no photosynthesis takes place in the roots.
Click for a 1 minute watch.
Question
What are Tap roots?
Define it, remember it.
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Tap root
* Where a plant has just one large fleshy root that is significantly larger than any lateral roots.
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Info Graphic
Adventitious Roots
This example in Strawberries.
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Adventitious Roots
In Strawberries.
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Info Graphic
Tap Roots vs Adventitious Roots
Comparing Tap to Adventitious roots.
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Tap Roots vs Adventitious Roots
Comparing Tap to Adventitious Roots.
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Question
Stolons are not part of the root system.
So what are Stolons?
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Stolons
* Are horizontal connections between organisms.
* They are a **stem NOT a root **that produce nodes from which new plants form.
Example in Strawberries, Runners are Stolons.
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Info Graphic
Stilt Roots on Maize
Stilt Roots on Maize
Info Graphic
Tuberous Roots
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Tuberous Roots
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Question
What are Tuberous Roots?
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Tuberous root
Is an enlarged fleshy root modified as a storage organ with shoots produced at one end and roots produced at the other.
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Info Graphic
Don’t confuse Tuberous roots with other Storage Roots.
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Potatoes and Dahlia’s are Tuberous
Bulbs, Carrots, Onions and Beetroot are not.
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Question
What are Aerial Roots?
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Aerial roots are roots that are above ground. They are grown for support. Ivy plants have them to cling to structures, such as stone walls, or other trees.
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What are the functions of these roots?
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Storage.
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Study card.
Rootcap
Reveal for 5 bullet points.
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Rootcap
* At the tip of every growing root is tissue called the root cap.
* It is not visible to the naked eye.
* It consists of tissue (parenchyma) with unthickened walls covering the apical meristem.
* The root cap provides protection to the meristem cells as the root goes through the soil.
* Cells can ware away but are quickly replaced by new cells generated by cell division within the meristem.
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Study Card
Root Epidermis
Reveal for 5 bullet points.
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Root Epidermis
* The root hairs of the epidermal cells increase the surface area through which movement of materials can occur.
* The thread like hairs are simply enlargements of the protoplast that extend outward into the soil.
* They have little wall material and are extremely fragile and easily broken.
* It is the outer layer and it forms a boundary between the plant and the environment.
* It protects against water loss, regulates gas exchange, absorbs water and minerals.
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Study Card
Cortex
Reveal for 4 bullet points.
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Cortex
* Made of parenchyma cells.
* Is the largest part of the primary root.
* Three layers of cortex are recognized: the hypodermis (also called exodermis), the endodermis and, between them, the storage parenchyma.
* Its function is transportation of material and also may be used as a food store.
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Study Card
Stele
Reveal for 3 bullet points.
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Stele
* The stele includes all of the tissues within the cortex.
* The pericycle - a cylinder of parenchyma.
* The vascular tissues—xylem and phloem on the inside in the roots.
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Podcast
Smarty Plants: How clever are plants?
36 minute listen
Roots
