Plants have two main vascular tissues: xylem and phloem. Xylem is responsible for transporting water and dissolved mineral salts from the roots upward to the leaves. Phloem, on the other hand, is the tissue responsible for translocation, which is the movement of manufactured food (mainly sucrose and amino acids) from the sites of production (typically leaves, where photosynthesis occurs) to sites of use or storage throughout the plant.
Phloem cells, specifically sieve tube elements and their companion cells, form a continuous pathway that carries dissolved organic nutrients bidirectionally: from leaves downward to roots, and from storage organs upward to growing tips, flowers, and fruits. This process is driven largely by pressure differences created by the active loading and unloading of sugars into and out of the sieve tubes.
The pericycle is a layer of cells in the root that gives rise to lateral roots. The endodermis is a single cell layer in the root that regulates which substances enter the vascular cylinder. Neither of these tissues is involved in the long-distance transport of food. Xylem vessels transport water, not manufactured food.
Exam tip: Remember the distinction: xylem moves water up, phloem moves food (sugars) to where the plant needs it.