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.