What is the Driving Force for the Movement of Solutes

Question

What is the driving force for the movement of solutes in the phloem of plants?
A)gravity
B)a difference in water potential (Ψ)between the source and the sink
C)root pressure
D)transpiration of water through the stomata
E)adhesion of water to phloem sieve tubes

Accepted Answer

The driving force for the movement of solutes in the phloem of plants is a difference in water potential (Ψ) between the source and the sink. This creates a pressure gradient that pushes the solutes from the source, where they are produced, to the sink, where they are used or stored. Gravity, root pressure, transpiration, and adhesion also play a role in plant transport, but they are not the primary driving force for solute movement in the phloem.