BRAINCAKERoot Pressure
Root pressure is a pressure that pushes water up the xylem from the roots. It is produced by the living cells of the root and requires energy.
It works as follows:
1. Cells of the endodermis actively transport mineral ions into the xylem, using ATP from respiration.
2. This lowers the water potential of the solution in the xylem.
3. Water moves into the xylem from the surrounding cells by osmosis.
4. The Casparian strip stops the ions leaking back out through the cell walls, so the extra water in the xylem creates a pressure that pushes water upwards.
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Key terms in this lesson
- casparian strip
- A waterproof band of suberin in the cell walls of the endodermis that blocks the apoplast pathway, forcing water and ions to cross a cell membrane.
More in Transport in Plants
- Adhesion and Capillarity
- Modelling Transpiration
- Measuring the Rate of Water Uptake
- Factors Affecting Transpiration
- Translocation in the Phloem
- Phloem Loading
- The Symplast Pathway
- The Apoplast Pathway
All 21 lessons in Transport in Plants · All Edexcel AS-level Biology topics