Transpiration

Question 1

Explain the pathway of water out of a leaf.

Answer 1

Water enters the leaf from xylem and moves by osmosis into spongy mesophyll cells.
Water evaporates from spongy mesophyll to air spaces.
Water vapour diffuses from air spaces out of stomata.

Question 2

How does light intensity effect rate of transpiration?

Answer 2

Higher light intensity, more stomata open, Greater rate.

Question 3

How does water availability effect rate of transpiration?

Answer 3

Lower water availability, more of hormone ABA produced, guard cells close, decrease in rate.

Question 4

How does temperature effect rate of transpiration?

Answer 4

Higher temperature, faster diffusion of water vapour, faster rate.

Question 5

How does humidity effect rate of transpiration?

Answer 5

Higher humidity,reduced water vapour concentration gradient, slower rate.

Question 6

How does wind effect rate of transpiration?

Answer 6

Windy, carry water vapour away maintaining water vapour concentration gradient, faster rate.

Question 7

What is the main assumption you make when using a potometer?

Answer 7

All the water taken up is transpired and non of it remains in the plant.