Gas Exchange & Transpiration Flashcards
Why does increasing humidity decrease the rate of transpiration???
Because it lowers the difference in water potential inside and outside the leaf, meaning a lower concentration gradient and slower evaporation by diffusion.
What is transpiration?
The movement of water from the root of the plant up to the stomata in the leaf via the Xylem.
What is the function of the waxy cuticle?
to reduce water loss from the leaf (by reflecting heat, preventing evaporation)
What does the phloem transport?
sugar solution and amino acids
How is the spongy mesophyll layer adapted for gas exchange?
Lots of air spaces to increase the surface area for more diffusion of carbon dioxide
What is the definition of diffusion?
The net movement of particles from an area of high concentration to an area of low concentration down a concentration gradient
What is the definition of osmosis?
The net movement of water molecules from an area of high water potential to an area of low water potential until dynamic equilibrium is reached
What are the two ways to measure transpiraiton in plants?
- mass potometer
- bubble potometer
where does carbon dioxide enter a plant from?
stomata
State 1 similarity between xylem and phloem
Both composed of specialized cells
What are the adaptations of leaves for photosynthesis?
Large surface area, Thin, Waxy Cuticle.
Why should the shoot be cut at an angle when measuring transpiration in plants?
Increase the surface area to avoid air bubbles into the Xylem
Where are vascular bundles found in the root?
In the centre
Why are vascular bundles found in the centre of the root?
To anchor the plant
1 factor that decreases transpiration
humidity
