Transpiration

Question 1

what is the definition of transpiration

Answer 1

loss of water through evaporation via the stomata from the leaves

Question 2

what are the factors which effect the rate of transpiration

Answer 2

• light intensity
• Temperature
  -Wind speed
• Humidity

Question 3

how does the light intensity effect the rate of transpiration

Answer 3

• the brighter the light, the greater the transpiration rate.
• the stomata is closed in dark
• photosynthesis can’t happen in dark as it needs light energy
• as photosynthesis is not happening the stomata doesn’t need to open to let co2 in
• when the stomata is closed very little water can escape

Question 4

how does temperature effect the rate of transpiration

Answer 4

the warmer it is the faster the rate of transpiration as water molecules have more kinetic energy

more energy to evaporate and diffuse out of the stomata

Question 5

how does wind speed effect the rate of transpiration

Answer 5

the higher the wind speed around the leaf the greater the transpiration rate

the wind blows the water away maintaining a low concentration of water particles around the leaf encouraging diffusion to occur

increasing transpiration
increasing concentration gradient

if the water is not blown away it means there remains a higher concentration of water particles around the leaf as well as inside it so it means diffusion doesn’t happen as quickly

Question 6

How does humidity effect the rate of transpiration

Answer 6

the direr the air the faster the rate of transpiration

osmosis will slow down
if the air is humid it holds more moisture(meaning their is a lot of water already in it)

this means there is not much of a difernece between the inside and the outside of the leaf

diffusion happens faster if there is a greater difference in the con grad ( really high conc and a really low conc)

Question 7

describe how a student could use a potometer to measure the rate of water taken up by the plant.

Answer 7

1. Cut shoot underwater at a slant (to avoid the risk of too many air bubbles)
2. place shoot under water creating one air bubble to measure.
3. measure the starting point before 1hr and the finishing point of the air bubble after the 1hr.
4. calculate the distance moved of the air bubble after 1hr.
5. repeat three times and calculate an average.