Transpiration and Stomata Flashcards
What is transpiration?
The loss of water from the plant.
What is transpiration caused by?
The evaporation and diffusion of water from the plant’s surface.
Where does most transpiration happen?
At the leaves.
Why does the water move up the plant?
The loss of water causes a slight shortage of water in the leaf, and so more water is drawn up from the rest of the plant through the xylem vessels to replace it.
What else ensures that there is a constant transpiration stream through the plant?
As water is pulled up, more water is drawn up through the roots.
What does the transpiration stream transport other than water?
Mineral Ions that are dissolved in the water.
What are stomata?
Tiny pores on the surface of the plant.
Where are stomata mostly found?
The lower surface of leaves.
What is the function of the stomata?
- To allow CO2 and oxygen to diffuse directly into and out of a leaf
- To allow water vapour to escape during transpiration
What is the singular of stomata?
Stoma
What causes water to escape from the leaves through the stomata?
Diffusion as there’s more water inside the plant than in the air outside.
What controls the size of the pores of the stomata and how?
Guard Cells.
They change shape.
Are stomata open or closed when the guard cells are flacid?
Closed
Are the stomata open or closed when the guard cells are tergid?
Open
