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What is the meaning of xylem and xylem function?


Xylem, a network of vessels in plants that carry water and dissolved minerals from the roots to other parts of the plant and also provides physical support. The xylem tissue consists of various special cells that contain water, known as tracheal elements. Together with phloem (tissue that carries sugar from the leaves to other parts of the plant), xylem is found in all vascular plants, including seedless club moss, ferns, horsetail, and all angiosperms (flowering plants) and gymnosperms (plants with seeds that are not seeds closed in the ovary).

The xylem tracheal elements consist of cells known as tracheids and vessel members, both of which are usually narrow, hollow, and elongated. Tracheids are less specialized than other vessel members and are the only type of water-producing cells in most gymnosperms and seedless vascular plants. Water that moves from the tracheid to the tracheid must pass through a thin modified primary cell wall known as a hole membrane, which serves to prevent the passing of damaging air bubbles.

The formation of xylem begins when root and bud cells divide which grow actively (apical meristems) giving rise to primary xylem. In woody plants, secondary xylem is the main part of a mature stem or root and is formed when the plant expands in circumference and builds new xylem rings around the original primary xylem tissue.

When this happens, the primary xylem cells die and lose conduction function, forming a hard skeleton that only functions to support plants. Thus, in the branches and branches of large older trees, only the outer secondary xylem (sapwood) functions in water conduction, while the inside consists of primary xylem which is dead but structurally strong. In temperate or cold climates, the age of a tree can be determined by counting the number of annual xylem rings formed at the base of the trunk (cut transversely).