Sucrose in unloaded from the phloem at any point to cells that need it- main mechanism of phloem unloading is by diffusion of sucrose form the phloem to surrounding cells.
Sucrose rapidly moves into other cells by diffusion or is converted into another substance so that a concentration gradient of sucrose is maintained between the contents of the phloem and surrouding cells.
Loss of solutes from phloem leads to a rise in the water potential- water moves out into the surrounding cells by osmosis- some of the water carried the solute to the sink is drawn into the transpiration stream in the xylem.
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