2.5 - Transport in Plants

Root hair cells take up water and mineral ions

• Plant roots take in water and dissolved mineral ions from the soil.
• Root hair cells on the surface of the root are adapted to do this efficiently.
• Each root hair cell grows out into a long, thin "hair" that sticks out into the soil, and a single root branch is covered in millions of them.
• Together the hairs give the root a very large surface area, which speeds up the absorption of water and minerals.
• Plants need mineral ions for healthy growth.

How each substance is absorbed

• Water - Absorbed into the root hair cells by osmosis, because the soil water is more dilute than the solution inside the cells.
• Mineral ions - Usually more concentrated inside the root hair cells than in the soil, so they can't be drawn in by diffusion. They're taken up against the concentration gradient by active transport, which uses energy released by respiration.