FACTORS AFFECTING RATE OF TRANSPIRATION
light intensity
does not affect evaporation of water
in daylight increased photosynthesis keeps stomata open
to increase CO2
but this allows water vapour to diffuse out
speeding up transpiration
humidity
temperature
air movement
evaporation of water more rapid into warm air / increased temperature
this cools the leaf and does not kill the plant
less water evaporation when it's cold
dry air increases transpiration
increased air movement increases water vapour
increases rate of transpiration
leaf structure
structures that reduce transpiration rate
- thick, waxy cuticle
- sunken stomata
- rolled up leaves, with stomata underneath
- needle-shaped