Transpiration
Biology: AQA GCSE Higher, topic 2.5.3
Transpiration (Water Transport)
Transpiration transports water and the minerals dissolved in it through the plant. Water moves in one direction only: from the roots to the leaves.
Root hair cells
- Root hair cells absorb water from the soil via osmosis (movement of water from a dilute solution to a concentrated solution).
- Mineral ions are taken up by active transport (movement of ions and molecules across a cell membrane to an area of higher concentration).
Xylem
- After being absorbed by the root hair cells, the water and minerals are carried in xylem vessels up the stem and into the leaves.
Leaves
- Once the water reaches the leaves, most of it evaporates and the water vapour diffuses out (is lost) through open stomata.
- Losing water from the leaves is called transpiration.
- This process of transpiration helps to pull water up from the roots.
Test yourself on Transpiration
Why do root hair cells absorb water from the soil via osmosis rather than active transport?
Why do root hair cells use active transport, rather than diffusion, to absorb mineral ions from the soil?
Why do root hair cells use two different processes to absorb water and mineral ions from the soil?