About this lesson
By examining a plants root system under the microscope, students will learn how plants obtain water from soil.
3, 4, 5, 6
Water and the natural environment
- understand the role a plant's root system plays in obtaining water from soil
- use a microscope to identify the different components of a plant's root system.
- Living things can be grouped on the basis of observable features and can be distinguished from non-living things ACSSU044
- Living things depend on each other and the environment to survive ACSSU073
- Living things have structural features and adaptations that help them to survive in their environment ACSSU043
- The growth and survival of living things are affected by the physical conditions of their environment ACSSU094
Humanities and social sciences (geography)
- The importance of environments, including natural vegetation, to animals and people ACHASSK088
Things you will need
- Weed plant samples (roots intact) from home or from the school ground (remove the plant with a spade as this will keep the root cap intact)
- Plastic gloves
- Cup of water
Please check with a parent/guardian before taking cuttings as some plants like oleander and lantana are dangerous, and some people may be affected by pollen or have allergies to plants like grevillea.
As a precaution ensure students wear gloves when collecting plant samples and wash their hands afterwards.
- Ask students: why do we water plants at the base of the plant into the soil rather than on the plant itself?
- Explain to students how plants absorb water from soil.
- Explain to students they will use their microscope to take a closer look at the roots of a plant and how they work to gain a better understanding of how plants source water from soil.
- Have students carefully wash the sand off the roots of their plant sample.
- Have students examine the plant and root system with the naked eye then record their observations.
- Students examine a single root under the microscope. Have them look closely at the tip of the root. Explain to them they should be able to see hair-like structures called root hairs. The plant takes up most of the water and minerals that it needs through these root hairs.
- Get students to describe what they see and record their observations.
Reflect & summarise
- Test students understanding by asking them to explain how plants absorb water from soil.
- Discuss why water wise plants are a suitable option for gardens in WA.
- Research the importance of root hairs and the root cap in plants.
- Research root adaptations in its root structure (e.g. a deep tap root or a wide spreading root structure). Relate this back to how a plant obtains water from soil (e.g. clover).
Teacher background information
How do plants obtain water from soil?
Some of our drinking water is obtained from underground supplies, and we have bores to pump it to the surface. Roots are a plant’s water bore. The root system brings water from the ground to the surface parts of the plant.
The root hairs are responsible for absorbing water and nutrients. Tube-like cells (xylem vessels) found in the stems then carry the water up to the leaves of the plant. This movement is referred to as capillary action (the attraction of the water molecules and the molecules of the xylem is what causes the water to be pulled up, much like the action of sucking a straw).
The benefits of waterwise plants
As WA continues to experience the effects of a drying climate, we all need to do our part to help reduce our water use. One way of doing this is to choose waterwise plants in our gardens. Waterwise plants are adapted to our climate and need less water than delicate species found in northern European style gardens. For example, eucalypts have toughened leaves and can turn their leaves to reduce the surface area facing the sun, while succulent plants like cacti can store water.
Did you know?
A carrot and turnip is actually just one big root, which is why they've adopted the name 'root vegetables'.
- Root: The part of a plant or tree that grows underground and obtains water from the soil
- Root cap: A hollow cone of loosely arranged cells that covers the tip of a plant's root and protects it during its journey through the soil
- Root hairs: Hair- like structures on a plant root that absorbs water and minerals from the soil
- Root system: The configuration of a plant's various roots
- Xylem vessels: Hollow tube-like cells responsible for transporting water from the roots. They may be seen as light cylindrical structures in the centre of the root