Name: Anatomy of Monocot Leaf
Uploaded: 2019-07-19
Duration: 3 min 43 s
Description: Monocot leaves are isobilateral with parallel venation. The vascular bundles are conjoint, collateral and closed. Bulliform cells are characteristic of monoc...

Question

What is xylem? Explain the structure of various kinds of components of xylem.

Accepted Answer

Complex tissues are heterogeneous in nature and are composed of different types of cell components. Xylem and phloem are the complex tissues that together form vascular bundles. The main function of the xylem is the conduction of water and inorganic nutrients from roots to the leaves. It also provides mechanical support to the plant. Xylem parenchyma act as storage of food like starch, fatty oils, tannins and crystals.

The xylem consists of four types of tissues such as tracheids, xylem vessels, xylem fibres and xylem parenchyma.

Tracheids: These are the elongated dead elements of the xylem with pointed ends. These are the fundamental cells in the xylem of ancient vascular plants and seedless plants. It is an elongated structure with tapering ends. When the cells attain maturity, then it becomes devoid of protoplasm. The cavity or lumen of the cells are empty. The walls are hard, lignified with bordered pits. These are connected with the adjoining cells through the pits. The main function of the tracheid is to conduct water and minerals. It also gives mechanical support to the plant. In some cases, it acts as a storage of water.

Xylem vessels: These are tubular structures and are much wider than tracheids. Cell walls are hard, thick and lignified. These are dead cells that are devoid of protoplasm. These are arranged end to end and on the top of one another such as a pipeline. Cell walls at both the ends degenerate when cells die. As a result, stacked vessels become continuous tubes. The structural component of the xylem.

Xylem parenchyma: The parenchyma cells which remain associated with the xylem are called xylem parenchyma or wood parenchyma. These cells are attached end to end in most plant. The cells may be thin or thick walled in secondary xylem these have lignified secondary walls. In this type the pit pairs are present. These are the only living cells in the xylem. These occur in two forms in the secondary xylem i) axial parenchyma - cells vertically arranged and ii) Ray parenchyma - cells horizontally arranged. These cells act as storage of food and also helps in water conduction.

Xylem fibres: These are of two types: libriform fibres and fibre-tracheids. These are intermixed with each other. Their main function is to provide mechanical support.

What is xylem? Explain the structure of various kinds of components of xylem.

Important Questions on Anatomy of Plants

Learn and Prepare for any exam you want !