- Ask pupils to suggest reasons why plants need water taken in by roots. Provide pupils with plants with growing root systems,
eg garlic cloves suspended over water, water lettuce, cress seedlings, or a video clip of growing roots. Discuss with pupils how the roots are adapted for taking in water.
- Challenge pupils to explain why plants in flooded or waterlogged soil die despite easy access to water and minerals.
- Ask pupils to examine roots with root hairs,
eg cress, or secondary sources,
eg prepared slides, animations, and to make their own annotated drawings showing how roots are adapted for their functions.
- Show pupils four pieces of evidence of movement of materials in plants,
eg root hairs on germinating mung beans, celery sticks which have been soaked in a dye to show movement up xylem vessels, a transverse section through a stem showing vascular bundles, and a leaf. Ask them to use the evidence to explain the movement of substances from the soil and through the plant, and to present their ideas diagrammatically.
- Review earlier work on the production of biomass. Ask pupils why farmers put fertilisers on fields. Provide boxes of plant fertiliser for pupils to explore the ingredients listed, and ask them to use secondary sources to find out why plants need certain minerals,
eg nitrate and potassium, for healthy growth.
|
|
- explain the functions of water in plants,
eg in photosynthesis, to transport minerals, to make the plant firm, for cell growth, to cool leaves, to form fruits
- describe how roots are adapted for taking in water,
eg by being spread out, being branched, having a large surface area, having root hairs
- describe how the root-hair cell is adapted for its function
- explain that root cells need oxygen supplies in the soil for respiration
- suggest how substances from the soil enter and move through the plant
- recognise that plants need mineral salts for growth
- relate a plant's need for nitrates to making protein and hence healthy growth
|
