As the chlorplasts of a leaf cell create more sugar, the excess is actively transported (translocated) from the cell into the phloem. The added particles make the solution in the phloem hypertonic. Water is drawn from the adjacent xylem sap and the increase volume in the same space results in an increase in osmotic pressure.
The increase in pressure can force the phloem sap toward various sinks (places where the pressure is reduced by removal of the sugar).
What metabolic processes can remove sugar?
