6. Transport in Plants - Xylem

What does xylem tissue transport?

water and mineral ions

Draw and label xylem tissue.

Describe the structure

Xylem vessels are very long, tube-like structures formed from dead cells (vessel elements) joined end to end.

transpiration meaning

The evaporation of water from a plant’s surface, evaporating through the stomata of the leaf down it’s water potential gradient.

Describe the cohesion tension theory, allowing water to move up the plant.

1. Water evaporated from the leaves at the top of the xylem, called transpiration.

2. This creates negative tension at the top, pulling the water upwards.

3. Water molecules are cohesive, so they stick together, pulling each other along, creating a column of water in the xylem, from the leaves down to the roots.

4. Water then enters the stem through the roots.

Factors affecting transpiration rate

light intensity

temperature

humidity

wind