2.55 Rate of Transpiration

- Transpiration is the loss of water through the leaf (caused by evaporation and diffusion through stomatal pore) 
- absorption of sunshine generates heat - transforms the water into heat 
- Concentration gradient for Water Vapour 
- if big difference then high rate of transpiration - factors: low humidity, high winds (wind blows away water vapour), high temperature (more evaporation), high light intensity ( higher rates of Photosynthesis) All result in FAST DIFFUSION 
- if small difference then low rate of transpiration - factors: high humidity, low wind speed (water vapour builds up around pore - gradient shallow), low temperature (less evaporation), low light intensity (rate of photosynthesis will be low and slow so water movement will be low and slow)