One of the main difference between xylem and phloem is that xylem can conduct substances only in one direction, whereas, phloem can transport substances in both directions.
Connective tissue
Xylem and phloem are two conducting tissues present in plants. Phloem transports food material from leaves to other parts of the plant body. It can conduct food in both directions. Xylem conducts minerals and water only in the upward direction i.e. from roots towards the stem.