translocation

Question 1

what is the mass flow hypothesis?

Answer 1

it is the idea that the translocation of glucose within the phloem is caused by a never-ending flow of water and mineral ions between the source and sink

Question 2

what are the steps of translocation?

Answer 2

1. sucrose produced in the mesophyll cells is actively transported into the sieve rube cell, water potential becomes more negative than adjacent xylem
2. sucrose is unloaded at sink cell, water potential of sieve tube cell increases snd becomes less negative than adjacent xylem and cells, water enters xylem by osmosis, lowering hydrostatic pressure
3. difference in hydrostatic pressure between sourceand sink causes mass flow of water, sucrose, and amino acids to move from leaves to roots as sap moves from a region of high hydrostatic pressure to low hydrostatic pressure