Monday, March 21, 2011
2.54 Transpiration
- Evaporation (liquid ---heat (sunlight) ---> gas) - through the stomatal pores
- Water taken up in roots (osmosis) - travels up stem - out through petiole - evaporation in leaf
- Sunlight warms the leaf allowing evaporation to take place so it can escape
- Not all sunlight is absorbed by chloroplasts some absorbed by other cell structures creating heat
- Water through xylem - moves through mesophyll - just above stomatal pore (little pocket) is where the phase change occurs from liquid to gas
- Water vapor gas diffuses through the pores - steep diffusion gradient
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just be be clear:
ReplyDeleteHeat causes the phase change to water vapour
Water vapour creates a 100% humidity in the spongy mesophyll space above the pore
The water vapour diffuses through the pore down a very steep gradient.