Question

The transport in xylem in usually unidirectional, whereas in phloem it is __.

Answer 1

The transport of water in the xylem takes place only from the roots to the leaves. Therefore, the movement of water and nutrients in the xylem is unidirectional. The movement of food in the phloem is bidirectional (both upward and downward), these organic solutes may be transported from the leaves where they are synthesized to the roots, where they are stored. Or it may be moved from the storage organs like roots, stem etc to the apical or lateral meristems during growth.