Plant organ system(transpiration) 4.2.3.2

Question 1

How does water get into a plant?

Answer 1

1. Absorbed from soil through root hairs
2. Transported up the stem to the leaves
3. Evaporated through the leaves (TRANSPIRATION)

Question 2

What is transpiration?

Answer 2

The evaporation and diffusion of water from inside leaves.

Question 3

What is the transpiration stream?

Answer 3

Water moves up the plant against gravity through xylem fuelled by evaporation

Question 4

Transpiration provides plants with water for:?

Answer 4

• Cooling
• Photosynthesis
• Support
• Movement of minerals

Question 5

How do we calculate the rate of transpiration?

Answer 5

• We assume that water uptake is equal to water loss by leaves.
• Using a stopwatch we record the distance moved by the air bubble in a fixed period of time.
• Other conditions must be kept constant!

Question 6

What are the factors affecting transpiration rate?

Answer 6

• light intensity
• temperature
• air movement
• humidity

Question 7

How does light affect transpiration?

Answer 7

-More light = increased transpiration because stomata open to allow more CO2 into the leaf and water to exit

Question 8

How does temperature affect transpiration?

Answer 8

-Higher temperature = increased transpiration because evaporation and diffusion are faster at higher temperatures

Question 9

How does wind affect transpiration?

Answer 9

Windy conditions = increased transpiration because water vapour is removed quickly by air movement, speeding up diffusion of more water vapour out of the leaf

Question 10

How does humidity affect transpiration?

Answer 10

Higher humidity = decreased transpiration because diffusion of water vapour out of the leaf slows down if the leaf is already surrounded by moist air