Notes

water evaporates from the leaves through stomata
carbon dioxide + water = glucose + oxygen
co2: from the air, enters the leaf through stomata
water: from the soil to the roots by osmosis and moves up the plant into the leaves through the xylem
02 leaves the leaf through stomata
stomata: are pores which allow gas exchanges in and out of the leaf
during the day when photosynthesis is happening:
co2 diffuses into the leaf
h2o: evaporates out of the leaf
02: diffuses out of the leaf
the stomata is surrounded by guard cells
these guard cells can chsnge their shape to open or close the stoma
when the stomata opens. co2 diffuses into the leaf and water leaves the leaf by evaporation
the evaporation of water from the leaf leads to a transpiration pull
transpiration pull: is the upward movement of water due to the continuous loss of water vapour through stomata
transpiration: is the loss of water vapour from plant leaves by evaporation of water at the surface of mesophyl cells followed by the loss of water vapour through stomata

transpiration can be measured in multiple ways:
1- potometer
2-whole plant change in mass
3-pressure sensors

Abiotic factors that affect transpiration rate:
light: transpiration rate increases with bright light
- the stomata opens wider to allow more carbon dioxide i for photosynthesis and thus more water will evaporate
temperature: transpiration rate is faster in higher temperatures
- evaporation and diffusion are faster in higher temperature
wind: transpiration rate is faster in windy conditions
- water vapour is moved quickly by the air movement so water vapour diffuse quickly out of the leaf
humidity: less transpiration
- diffusion of water vapour out of the leaf slows down if the leaf is surrounded by moist air