Translocation Flashcards
1
Q
What is translocation?
A
- mass transport of assimilates from source to sink via the phloem
2
Q
Describe what happens in translocation?
A
- hydrogen ions are actively pumped from inside the companion cells to outside
- hydrogen ions move down concentration gradient via co transport proteins that also transport sucrose
- sucrose in companion cells move to the sieve tube elements via the plasmodesmata
- there is a lower water potential in the sieve tube elements so water moves from companion cells
- mass flow of assimilates from an area of high pressure to low
3
Q
What is transpiration?
A
- the loss of water vapour from leaves
4
Q
What are the factors that affect transpiration?
A
- light intensity
- temperature
- air movement
- humidity
5
Q
Why is sucrose transported as an assimilate and not glucose?
A
- because glucose is reactive and so can take part in reactions on the way