B2- Transpiration And Stomata Flashcards
What are the four main factors that affect transpiration rate?
- Light Intensity
- Temperature
- Air Flow
- Humidity
How does light intensity affect transpiration rate?
The brighter the light, the greater the transpiration rate. Stomata close in the dark.
What happens to stomata when it gets darker?
Stomata begin to close, reducing water escape.
How does temperature influence transpiration?
The warmer it is, the faster transpiration occurs due to increased energy of water particles.
What is the effect of air flow on transpiration rate?
Better air flow increases transpiration rate by maintaining low water concentration outside the leaf.
What happens to transpiration rate in humid conditions?
The drier the air, the faster transpiration happens due to greater concentration difference.
What is a potometer used for?
To estimate the rate of transpiration by measuring water uptake by a plant.
What is the relationship between water uptake and transpiration?
Water uptake by the plant is directly related to water loss by the leaves.
What shape do guard cells have and why?
Guard cells have a kidney shape which allows them to open and close the stomata.
What happens to guard cells when the plant has lots of water?
They fill with water, become plump and turgid, causing stomata to open.
What occurs in guard cells when the plant is short of water?
Guard cells lose water, become flaccid, and close the stomata.
Describe the structure of guard cells.
Thin outer walls and thickened inner walls facilitate the opening and closing of stomata.
When do guard cells close stomata?
They close at night to save water while preventing loss of photosynthesis.
Where are stomata usually found on a leaf?
More stomata are found on the undersides of leaves than on the top.
Why are there more stomata on the underside of leaves?
The lower surface is shaded and cooler, resulting in less water loss.
