Understandings:
- Transpiration is the inevitable consequence of gas exchange in the leaf.
- Plants transport water from the roots to the leaves to replace losses from transpiration.
- The cohesive property of water and the structure of the xylem vessels allow transport under tension.
- The adhesive property of water and evaporation generate tension forces in leaf cell walls.
- Active uptake of mineral ions in the roots causes absorption of water by osmosis
- Adaptations of plants in deserts and in saline soils for water conservation.
- Models of water transport in xylem using simple apparatus including blotting or filter paper, porous pots and capillary tubing.
- Drawing the structure of primary xylem vessels in sections of stems based on microscope images.
- Measurement of transpiration rates using photometers. (Practical 7)
- Design of an experiment to test hypothesis about the effects of temperatures or humidity on transpiration rates.
- Use models as representations of the real world-mechanisms involved in water transport in the xylem can be investigated using apparatus and material that show similarities in structure to plant tissues.
Powerpoints
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