bubble potometer

Question 1

What does a bubble potometer measure?

Answer 1

water uptake into a plant

Question 2

Describe the set up of a bubble potometer

Answer 2

-plant that’s been cut at the stem, connected to a fine capillary tube filled with water
-tube connected to syringe filled with water in middle
-other end under water in beaker

Question 3

How does a bubble potometer work?

Answer 3

-set up potometer
-remove capillary tube from water to let air bubble form then replace back in beaker
-as water evaporates
from plant, water is drawn into stem so air bubble moves
-can calculate water uptake into plant by how far air bubble moves in given time

Question 4

What are some considerations when setting potometer up?

Answer 4

-place cut stem into water and cut 1cm off to avoid air being sucked into xylem vessels
-potometer should by fully sealed(petroleum jelly)
-allow plant to adapt to surroundings for 10 mins
-assemble potometer under water
-dab the leaves dry

Question 5

In what unit should you express your results?

Answer 5

volume of water lost per mm2 per minute

Question 6

How do you calculate this unit?

Answer 6

volume of water=area of capillary tube x distance moved by air bubble

mm2= draw around edge of each leaf and calculate surface area