1. Roots:
* Root hairs: These tiny extensions of root cells increase surface area for absorption of water and dissolved minerals from the soil.
* Xylem: This specialized vascular tissue within the roots forms a continuous network of tubes that extends up the stem and into the leaves.
2. Stem:
* Xylem: The water moves upwards within the xylem vessels, which are dead, hollow cells joined end to end.
3. Leaves:
* Xylem: The xylem network continues into the leaves, branching out to supply water to all leaf cells.
* Leaf veins: These are bundles of xylem and phloem that extend throughout the leaf.
* Stomata: Tiny pores on the underside of leaves allow for gas exchange. Water vapor also escapes through these pores, driving the movement of water upwards.
The Process:
* Absorption: Water is absorbed by the root hairs through osmosis, a process where water moves from an area of high concentration (soil) to an area of low concentration (root cells).
* Transpiration: Water evaporates from the leaves through stomata, creating a negative pressure (tension) that pulls water upwards through the xylem.
* Cohesion and Adhesion: Water molecules are attracted to each other (cohesion) and to the walls of the xylem (adhesion). These forces help maintain a continuous column of water.
Key Points:
* The upward movement of water is primarily driven by transpiration, the loss of water vapor from leaves.
* The xylem is essential for transporting water, providing a continuous pathway from roots to leaves.
* Water movement is a complex process involving osmosis, tension, and the properties of water molecules.
