potomoters

Question 1

What does a potomoter do?

Answer 1

= measures the rate of uptake of water from a plant
= water uptake is porportional to to transpiration this is used to indicate the rate of transpiration
= can be used to detect the affect of a named environmental variable on the rate of treanspiration

Question 2

Why must the sample of the plant be cut from a plant underwater?

Answer 2

= prevent air entering the xylem
+ breaking the water collumn
= potomoter is filled

Question 3

What is the potomer filled with and why?

Answer 3

= water
= dry of leaves
= air bubbles are removed

Question 4

How does this work?

Answer 4

= one air bubble is introduced to the equipment and and the distance the air bubble has moved towards the plant is recorded

Question 5

How do we calculate transpiration rate?

Answer 5

= the distance the bubbled moved used to wiork out the volume of water in the tube evapirated
= volume divided by time to get rate
=

Question 6

Why must the apparatus be set up in in plant shoot and underwater?

Answer 6

= cohesion tension theory, creating a negative pressure if cut in air, would draw air into the tube,
= break continous water collumn
=prevent transpiration

Question 7

Why are joints in apparatus covered in petroluem jelly?

Answer 7

= waterproof
= prevents water leakage
= ensure all water leaves by evapiration at the stomata

Question 8

Why may it not determine te rate of transpiraton?

Answer 8

• producyed in respiraion
  = used in phtosynthess=
  uses for support