6.9 - Transpiration and the Stomata Flashcards
What is transpiration?
Transpiration is the loss of water vapor from the leaves and stems of the plant.
What causes transpiration?
Transpiration is a consequence of gaseous exchange, as the stomata are open.
Where does water evaporate during transpiration?
Water evaporates at the open stomata (pores) on the leaf surfaces.
How does transpiration affect water movement in plants?
When some water molecules leave the plant, the rest are pulled up through the xylem, resulting in a continuous transpiration stream.
What are guard cells?
Guard cells are specialized cells that close and open stomata.
What is the shape of guard cells?
Guard cells are kidney-shaped.
What are the structural characteristics of guard cells?
Guard cells have thin outer walls and thick inner walls.
What happens to guard cells when water is abundant?
When lots of water is available, guard cells fill and change shape, opening the stomata.
What role do guard cells play in gas exchange?
Open stomata allow gases to be exchanged and more water to leave the plant via evaporation.
Where are most stomata located on a leaf?
More stomata are found on the bottom of the leaf.
Why are stomata primarily located on the bottom of the leaf?
This minimizes water loss by evaporation as the lower surface is shaded and cooler.
