Transport in the xylem of plants |
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 |
Application: Adaptations of plants in deserts and in saline soils for water conservation. |
Skill: Drawing the structure of primary xylem vessels in sections of stems based on microscope images |
Application: Models of water transport in xylem using simple apparatus including blotting or filter paper, porous pots and capillary tubing
Skill: Measurement of transpiration rates using potometers. (Practical 7)
Skill: Design of an experiment to test hypotheses about the effect of temperature or humidity on transpiration rates.
Skill: Design of an experiment to test hypotheses about the effect of temperature or humidity on transpiration rates.
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