4.8 Evaporation and transpiration

Question 1

What is key to transpiration in a plant?

Answer 1

Stomata

Water is lost through the stomata which opens to let in carbon dioxide for photosynthesis

Question 2

What is the mean? How do you calculate it

Answer 2

Average

Add all numbers and divide by number of objects

Question 3

Why is it important that leaves can open and close their stomata?

Answer 3

To increase and decrease water loss of water vapours

Question 4

Anything that effects the rate of evaporation will also affect ————-?

Answer 4

transpiration

Question 5

What is the transpiration system?

Answer 5

As water is evaporated from the surface of the leaves more water is pulled up through the xylem to take its place.
(driven from evaporation from the leaves)

Question 6

What are stomatos for?

What do they let in and out?

Answer 6

They are opened when the plant needs to allow air into leaves

• Carbon dioxide from atmosphere diffuses into the airspaces (and the cells)
• Oxygen produced by photosynthesis is removed from the leaf by diffusion into the air.

Question 7

What does a guard cell do?

Answer 7

Control the size of the stomata and their opening and closing.

Question 8

What are stomatas?

Answer 8

small openings all over leaf surface surrounded by guard cells

Question 9

What causes transpiration?

Answer 9

Evaporation and diffusion of water from a plants surface. Most happens at the leaves

Question 10

Explain how water moves up a plant in the transpiration stream?

Answer 10

As water evaporates from leaf surface, more water is pulled up through
xylem to replace it.
Water moves into roots by osmosis to replace water moving up xylem.
Transpiration stream is constant movement of water molecules through
xylem from roots to leaves.