Water flows into the source end of a sieve tube because

Question

Quizplus · Accepted Answer

Water flows into the source end of a sieve tube because sucrose has been actively transported into the sieve tube, making it hypertonic. This creates a gradient that causes water to move into the tube by osmosis, from an area of higher water potential outside the tube to an area of lower water potential inside the tube. The active transport of sucrose into the sieve tube is performed by companion cells, which are connected to the sieve tube by plasmodesmata.

Water Flows into the Source End of a Sieve Tube