Transportation and Evaporation in Plants

Question 1

What does the phloem carry, and what is this process called?

Answer 1

It carries dissolved sugars from the leaves to the rest of the plant. This is called translocation.

Question 2

What does the xylem carry?

Answer 2

Water and mineral ions from the roots to the stem, leaves and flowers.

Question 3

Why do plants need transport?

Answer 3

• All the cells in the plant need the sugar from photosynthesis.
• Sugar and mineral ions are needed for growth.
• Water is needed for photosynthesis.
• Water is needed to support the cells.

Question 4

Where do gases diffuse in and out of leaves through? What is the size of these controlled by?

Answer 4

Gases diffuse through stomata, and the size of these are controlled by guard cells.

Question 5

What is the process of evaporation of water at the surface of leaves?

Answer 5

Transpiration.

Question 6

What can the plant do to prevent excess water loss?

Answer 6

The guard cells can close the stomata.

Question 7

Why are there mitochondria in root cells?

Answer 7

Energy is needed for water and mineral ions to travel against the concentration gradient up the plant through the xylem.

Question 8

What factors can affect the rate of transpiration?

Answer 8

• Temperature - Molecules move faster, the rate of diffusion increase, the rate of photosynthesis increases so more stomata open.
• Humidity - Rate of diffusion is faster in DRY air.
• Airflow - Windy conditions increase the rate of evaporation.
• Light intensity - More light means an increased rate of photosynthesis.

Question 9

How can plants control water loss?

Answer 9

• Waxy cuticle is thick and shiny in hot environments.
• Most stomata are under the leaf.
• Leaves can collapse to reduce surface area.
• The stomata can close, which stops photosynthesis.