What Is the Difference Between Xylem and Phloem?

difference-between-xylem-phloem Credit: [Duncan]/CC-BY 2.0

Though xylem and phloem are both a part of the transportation system of plants, they transport different things. Xylem transports water and dissolved minerals. Phloem transports sugars throughout the plant.

Xylem conducts fluids from the roots of the plant to the top of the plant. Xylem tissues are connected in a straight line to facilitate the movement of the water and minerals. Old xylem tissue dies and new xylem tissue is produced each year. This is evidenced by the growth rings that are found in trees when they are cut down. Phloem does not die each year. It is spread throughout the plant and works to take the products of photosynthesis to the necessary locations for plant growth.

Both xylem and phloem are arranged close to each other in vascular bundles. The specific arrangement of the xylem and phloem varies between different plant types. In a collateral arrangement, the xylem and phloem are beside each other. In a bicollateral arrangement, the xylem is located between two columns of phloem. Amphivasal arrangements result in the phloem being surrounded by xylem, while amphicribral arrangements are exactly the opposite, with the xylem being surrounded by the phloem. Both xylem and phloem originate from cells in the apical meristem.