Transport Of Water In Xylem Flashcards
1
Q
What is transport of Atwater in the xylem called
A
Transpiration
2
Q
4 things that effect transpiration
A
- humidity
- wind
- temperature
- light
3
Q
How does temperature affect transpiration
A
- more kinetic energy faster rate of diffusion
4
Q
How does light effect transpiration
A
Higher rate of photosynthesis as stoat open to let out more co2 to diffuse into leaf and water out
5
Q
How does humidity affect transpiration
A
Higher humidity the lower the rate of transpiration More water in air Increased water potential Reduced diffusion gradient Slower rate of diffusion
6
Q
How is the xylem adapted for its function
A
Thick wall - withstand tension
No cytoplasm - maintains a continuous column of water
Pits in walls allows for lateral flow movement
No end walls - maintains continuous flow
7
Q
Theory of how water moves
A
Cohesion theory
8
Q
Cohesion tension theory
A
- water evaporates from leaf due to heat from the sun
- wp at stomata decreases
- water is drawn out of the xylem to replace water lost this creates tension
- water is pulled up across mesophyll cells and down xylem vessels as a continuous unbroken column this due to water molecules cohesion due to strong hydrogen bonds between molecules
- water evaporates through leaf
