Respond to this question: "If a plant doesn't have enough water to openits guard cells, how would this affect its rate of transpiration?" In your answer, discuss the following:
- the guard cell's role in transpiration
- what effect this would have on the stomata
- how this would affect the overall transpiration rate
This is my answer:
A pair of guard cells shaped like to cupped hands surround a stoma. Changes in the shape of guard cells cause stomata to open or close. When the guard cells take in water, they swell, but extra cellulose strands in their cell walls allow the cells to increase in length but not in diameter. Because of this, guard cells that take in water bend away from each other, opening the stoma and letting transpiration continue. When water leaves the guard cells, they shorten and move closer to each other, closing the stoma and stopping transpiration. Thus, the loss of water from guard cells causes stomata to close, stopping water loss.
Is this all right?
Thanks
-MC
it is OK
Yes, your answer provides a clear explanation of the role of guard cells in transpiration and how the lack of water would affect the stomata and overall transpiration rate. Well done!
To further expand on your answer:
The guard cells play a crucial role in regulating the opening and closing of stomata, which are tiny openings found on the surface of leaves. Stomata allow for the exchange of gases, such as the intake of carbon dioxide and the release of oxygen during photosynthesis, as well as the loss of water vapor through transpiration.
When the guard cells take in water, they become turgid and expand, causing the stomata to open wider. This allows for an increased exchange of gases and water vapor to occur. However, if a plant does not have sufficient water, the guard cells won't be able to take in as much water, causing them to lose turgidity and become flaccid. As a result, the stomata will partially or even fully close, reducing the rate at which water vapor is released.
This decrease in the opening of stomata due to the lack of water in the guard cells directly impacts the overall transpiration rate. With fewer open stomata, there will be a reduction in the surface area available for water evaporation. Consequently, the plant will transpire at a slower rate, reducing its overall water loss.
So, the combination of the guard cell's role in opening and closing stomata, along with their response to the availability of water, directly influences the rate of transpiration in a plant.