transpiration

Question 1

what is transpiration

Answer 1

loss of water vapour from the upper parts of the plants

Question 2

where is the most common area for water vapour loss

Answer 2

stomata

Question 3

what is the typical pathway for water leaving the leaf

Answer 3

water enters xylem
osmoses to the spongy mesophyll layer
water then evaporates from the spongy mesophyll layer and water vapour escapes out of open stomata

Question 4

what is the water vapour potential gradient

Answer 4

distribution of concentration of water vapour inside of a cell compared to outside

e.g. a high wvpg needs to be higher inside the leaf than outside for water vapour to diffuse out

Question 5

why is transpiration important

Answer 5

maintain cell turgor pressure
supplies water for growth
water evaporation cools plant down on a hot day
transports useful minerals up the plant

Question 6

what factors influence transpiration

Answer 6

light intensity
temperature
relative humidity
air movement
water availability

Question 7

how does light intensity impact transpiration

Answer 7

in light, stomata open for gaseous exchange for photosynthesis.
high light intensity= HIGHER RATE OF transpiration

Question 8

how does temperature impact transpiration

Answer 8

increases rate of evaporation of water molecules in the spongy mesophyll layer
water molecules have more kinetic energy
decreases water vapour potential outside the leaf, therefore faster diffusion of vapour out of stomata

Question 9

how does humidity affect transpiration

Answer 9

decreases rate of water loss, the water vapour potential gradient will be small between the inside and outside of the leaf.

Question 10

how does wind affect transpiration

Answer 10

carries water vapour that has diffused out of stomata away, therefore water vapour potential gradient remains high

Question 11

how does water availability impact transpiration

Answer 11

little water in soil, plant cant replace water lost by transpiration- causing leaves to wilt