BIOL-1507EL Lecture 6: Transportation
21 Jan 2018
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Document Summary
Stomata opening and closing continued: the changes in turgor pressure that open and close stomata result primarily from reversible absorption and loss of potassium ion (k+) by the guard cell. Stomata closure parallels a migration of k+ from the guard cells, which lead to osmotic loss of water. The k+ fluctuations passing the guard cell membrane are probably coupled to the generation of membrane potential by proton pumps. In general, the stomata open during day and close at night. However, there are three factors that contribute to stomata opening and closing: light stimulates guard cells to accumulate k+ ions and become turgid. Subsidiary cell: a plant epidermal cell that is located next to a guard cell in the stoma of a leaf and differs in structure from other epidermal cells. Mesophyll: the inner tissue (parenchyma) of a leaf, containing many chloroplasts. Imbibition: movement of water molecules in to the substances such as, wood or gelatin.
