Biology 2601A/B Lecture Notes - Lecture 16: Guard Cell, Stoma, Dicotyledon
10 Dec 2018
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Pores in the leaf surface that allow access from the outside to air spaces inside leaf: >90% of gas exchange (other 10% diffusion through leaf/stem cuticle) Can open and close, plant is able to regulate gas flow. Open is good for co2 uptake but bad for water loss. Gasses move from regions of high pgas to regions of low pgas. We can control the rate of gas exchange through manipulation of area. When stomates are open = a is large, more gas diffuses. When stomates are closed = a is small, less gas diffuses. Guard cell: have a space between cells, can be closed quite tightly or open. When stomates are open there is high water vapor inside and low water vapor outside. There"s movement of water from outside to inside. Path of resistance is through whether the stomates are open or closed.
