Xylem is the specialised tissue of vascular plants that transports water and nutrients from the plant–soil interface to stems and leaves, and provides mechanical support and storage. The water-conducting function of xylem is one of the major distinguishing features of vascular plants.

Conducting cells called elements are the part of xylem where water and minerals are transported.

botany. Alternative Title: conducting tissue.

The constituent elements of these systems are water-conducting cells (WCCs), which conduct water and nutrients, and food-conducting cells (FCCs), which conduct carbohydrates and amino acids (Ligrone et al., 2012; Lucas et al., 2013; Raven, 2003; van Bel, 2003).

Xylem, plant vascular tissue that conveys water and dissolved minerals from the roots to the rest of the plant and also provides physical support.

What are the components of xylem?

• Tracheids.
• Xylem vessels.
• Xylem fibres.
• Xylem parenchyma.

xylem parenchyma

The living elements include parenchyma, companion cells and sieve tubes.

Xylem parenchyma is not connected with the function of conduction of the plant. Explanation: Xylem consists of xylem parenchyma, sclereids, xylem vessels and tracheids. Xylem parenchyma is not concerned with transportation of water.

Phloem is composed of various specialized cells called sieve tubes, companion cells, phloem fibres, and phloem parenchyma cells.

Companion cells have a nucleus, are packed with dense cytoplasm contain many ribosomes and many mitochondria. This means that the companion cells are able to undertake the metabolic reactions and other cellular functions, which the sieve element cannot perform as it lacks the appropriate organelles.

The companion cells are specialized parenchyma cells in the phloem tissues of the angiosperms. They are nucleated living cells with several ribosomes, plastids, and mitochondria. Their nuclei and nucleoli are relatively large (an indication of being metabolically active).

phloem cells

phloem

Phloem tissue consists of conducting cells, generally called sieve elements, parenchyma cells, including both specialized companion cells or albuminous cells and unspecialized cells and supportive cells, such as fibres and sclereids.

4.3 The companion cells-sieve elements complex It must function in several roles, including phloem loading and unloading, long-distance transport, and as a quality control center for monitoring the nature of substances passing into and out of the phloem.

The cells that make up the phloem are adapted to their function: Sieve tubes – specialised for transport and have no nuclei. Each sieve tube has a perforated end so its cytoplasm connects one cell to the next. One or more companion cells attached to each sieve tube provide this energy.

Root hair cells are adapted for taking up water and mineral ions by having a large surface area to increase the rate of absorption. They also contain lots of mitochondria , which release energy from glucose during respiration in order to provide the energy needed for active transport.