1.Transpiration is the inevitable consequence of gas exchange in the leaf.

• Define transpiration.

• Outline gas exchange that occurs through leaf stomata.

2. Plants transport water from the roots to the leaves to replace losses from transpiration.

• Outline structures and mechanisms involved in the flow of water from roots to leaves. ​

3. The cohesive property of water and the structure of the xylem vessels allow transport under tension.

• Describe structure of xylem.

• Outline how xylem is able to maintain rigidity even under low pressure or mechanical disturbance.

• Outline polarity of water molecule.

• Define cohesion.

4. The adhesive property of water and evaporation generate tension forces in leaf cell walls.

• Explain the decrease in pressure and transpiration-pull that results from evaporation of water from the leaf.

• State the transpiration is a passive processes.

5. Active uptake of mineral ions in the roots causes absorption of water by osmosis.

• Explain why roots are hypertonic relative to the soil.

• Outline the role of active transport in maintaining root tonicity.

• Describe how water enters roots from the soil.

• Compare the symplastic and apoplastic pathways of water transport through the root.

1. Adaptations of plants in deserts and in saline soils for water conservation.

• Define xerophyte and halophytic.

• Outline strategies used by xerophytes and halophytes to reduce water loss. ​

2. Models of water transport in xylem using simple apparatus including blotting or filter paper, porous pots and capillary tubing.

• Explain use of models in science.

• Describe simple models of water transport, inclusive of evaporation, adhesion and cohesion. ​

1. Drawing the structure of primary xylem vessels in sections of stems based on microscope images.

• Draw a xylem vessel tube, labeling cellulose wall and helical lignin thickening.

2. Measurement of transpiration rates using potometers. (Practical 7)

• Describe the use of a potometer to measure transpiration rates.

3. Design of an experiment to test hypotheses about the effect of temperature or humidity on transpiration rates.

• ​Identify the manipulated, responding and controlled variables in an experiment to test the effect of an abiotic factor on the rate of transpiration.