Topic 3- Movement in the phloem

Question 1

What is translocation?

Answer 1

the transport of assimilates/organic substances from source to sink and requires the input of metabolic energy (ATP)

Question 2

What is the liquid that is being transported (found within phloem sieve tubes)?

Answer 2

Phloem sap

Question 3

What does phloem sap consist of?

Answer 3

-Sugars (mainly sucrose)
-Water
-Other dissolved substances: amino acids, hormones and minerals
-Assimilates are dissolved within the sap

Question 4

Give some examples of sources

Answer 4

-Green leaves and green stem (photosynthesis produces glucose which is transported as sucrose, as sucrose has less of an osmotic effect than glucose)
-Storage organs
-Food stores in seeds (which are germinating)

Question 5

Give some examples of sinks

Answer 5

-Meristems which are actively dividing
-Roots that are growing/actively absorbing mineral ions
-Any part of the plant where the assimilates are being stored

Question 6

Is this process active or passive: Loading+ unloading of sucrose from source to phloem to sink?

Answer 6

Active

Question 7

What two factors impact this process?

Answer 7

-High temps
-Resipiratory inhibitors

Question 8

What is the pholem?

Answer 8

A tissue