Question

Expalin why xylem transport is unidirectional and phloem transport is bi directional?

Answer 1

In plants, the source and sink association is variable. The phloem conducts the transportation of foods from source to the sink and it can be bi-directional (upward and downward) depending on the necessity. The phloem sap transports food synthesized in leaves to all part of the plants and in any direction. The xylem transport water from roots to the leaves only; hence, the water and nutrient movement within xylem tissue is uni-directional.