2.54 Transpiration

Transpiration: evaporation of water from the surface of a plant

H2O (l) ---> H2O (g)

Heat + sunlight (light energy converts to heat as structure of leaf absorbs light)

evaporation through stomatal pores

Water transport = root -> stem -> leaf (by xylem) -> (gas) stomatal pores

Chloroplasts not absorbing all the light - some absorbed by other cell structures

water ---> (xylem) ----> mesophyll layer (spongy)

above stomatal pore: phase change - liquid -> gas (evaporation)

Gas diffuses through pore (steep diffusion gradient)

- humidity

Summary

1. sunlight warms leaf

2. liquid -> gas from heat

3. diffusion