NEET UG » NEET UG Study Material » Biology » Xylem Parenchyma

Xylem Parenchyma

Xylem parenchyma is a component of the complex tissue known as Xylem. Cells in the parenchyma of the xylem are primarily responsible for the storage of carbohydrates, lipids and water conduction.

A tree’s xylem derives from the Greek word xylon, which means wood. Xylem is a form of vascular tissue found in plants that is largely responsible for transporting water and nutrients from the roots to the stem and leaves of the plant. They also help to strengthen the mechanical strength of the plants. There are two types of xylem cells that are distinguished by their origin: Primarily derived from the procambium, primary xylem is further subdivided into protoxylem and metaxylem. Secondary xylem is derived from the cambium of the vascular cambium.

There are four different types of components that make up the xylem:

  • Tracheids are tube-like cells that have died and have a tapering end. 

Generally speaking, they are found in the gymnosperm and lower angiosperm. 

They have a thick lignified wall and no protoplasm, which makes them difficult to identify. 

Their primary purpose is the conveyance of water and minerals.

  • Vessels:

Angiosperms are characterised by the presence of vessels.

These have the appearance of a tube because they are a long cylindrical construction. 

The walls are lignified, and there is a big central chamber in the structure. 

They are made up of a number of cells known as vessel members, which are linked together by a perforation in the common walls. 

It is primarily responsible for the transport of water and minerals, as well as the provision of mechanical strength to the plant.

  • Xylem fibre: 

A decomposing cell with lignified walls and a central lume.

It is involved in the transportation of water and the provision of mechanical support.

  • Xylem Parenchyma:

 Xylem parenchyma is made up of only live cells that store starch and fat. 

They contribute to the movement of water over short distances.

The Xylem Parenchyma’s Internal Structure

The parenchyma cells that are connected with the xylem are referred to as xylem parenchyma.

In secondary xylem, there are two major types of parenchyma cells: 

  1. Axial parenchyma cells are organised in a circular pattern around the axis.

  2. Radial parenchyma cells are arranged in a ray pattern, radiating outward from a common point.

Characteristics of xylem parenchyma 

The following are the primary characteristics of xylem parenchyma:

  1. The xylem contains only live cells.

  2. The cell wall is made of cellulosic material and is thin.

  3. They are distinguished by the presence of a conspicuous nucleus and protoplast.

  4. The cells are colourless and contain numerous big vacuoles.

  5. Parenchymal cells that are still alive can be seen in both the primary and secondary xylem.

  6. Seasonal variations in the fat and storage protein levels of parenchymal cells have been observed.

  7. These cells have lignified walls with secondary thickening and may be subdivided by septa.

  8.  Crystal-containing parenchyma cells have thickened walls with secondary thickening.

  9. Chloroplasts are found in the xylem parenchyma cells of herbaceous plants and the ray parenchyma cells of woody plants.

  10.  Chloroplasts are found in the xylem parenchyma cells of herbaceous plants and the ray parenchyma cells of woody plants.

  11. Tyloses are outgrowths that are formed by both axial and ray parenchyma cells that are located next to blood vessels.

  12. Contact cells refer to the parenchyma cells that give birth to tyloses in the intestine.

  13. The nucleus and cytoplasm of xylem parenchyma cells migrate into tyloses as they move through the xylem.

  14. Tyloses are capable of storing a wide range of chemicals and developing secondary walls.

  15. Some tylose may differentiate into sclereids as a result of this process.

Functions of Xylem Parenchyma

The following are the primary roles of the xylem parenchyma:

Food stuff is stored in the form of starch, lipids, tannins, and crystals, among other forms.

The ray parenchymatous cell is responsible for the transmission of water radially.

Tyloses, which are outgrowths of the xylem parenchyma cells, form a close connection between the cells and the vessels or tracheids.

Tyroses protect vascular tissues from harm when there is a drought or an infection present.

The function of xylem parenchyma cells is to maintain the capacity of the xylem transport system.

These individuals are responsible for the restoration of vessel and tracheid functions when the cavity becomes blocked due to the presence of an air bubble in the cavity (embolism).

It is caused by the high water tension that exists in the xylem tissues that cavitation occurs.

Xylem Parenchyma

It is one of the most significant and only live components of the xylem, making it one of the most important and only living components in the body. 

However, its cellulose cell walls are extremely thin, despite the fact that it has a large amount of cytoplasm and a recognisable nucleus. 

The absence of a lignified cell wall is the most notable feature of this specimen. 

Furthermore, secondary growth occurs only on an irregular basis in the secondary xylem of the plant. 

These cells are primarily involved with the storage of carbohydrates and fat, and they may be able to promote the transfer of water over short distances if the environment is favourable.

Conclusion

These cells, which are found in the trunks of woody plants and are colourless, are thought to be responsible for storing starch, oils, and other ergastic compounds in the trunks of woody plants.

It is possible that dangerous chemicals are present in the inclusions of xylem parenchyma cells.

The wood of flowering trees, in particular, contains two basic types of parenchyma cells: axial (i.e., parenchyma cells arranged around an axis) and radial. 

Some axial and radial parenchyma cells, on the other hand, may develop secondary thickenings at the edges of their cell membranes.

Sclerenchyma cells are parenchyma cells that have developed secondary cell walls in addition to their primary cell walls.

faq

Frequently asked questions

Get answers to the most common queries related to the NEET UG Examination Preparation.

What is the significance of xylem parenchyma being living cells?

Answer: The only cells that can be found in the xylem are the parenchyma cells. Thin cell walls, big vacuoles, a con...Read full

What is the composition of Xylem?

Answer: The xylem is a complicated organ. Four constituents make up the xylem:  ...Read full

What is the most important function of the xylem?

Answer: The primary purpose of the xylem is to transfer water from the roots to the rest of the plant’s struct...Read full

What are the two forms of parenchyma?

Answer: Chlorenchyma is a form of parenchyma that is primarily involved in photosynthesis and is distinguished from ...Read full

Where do secondary xylem originate?

Answer: Secondary xylem originate from the cambium of the vascular cambium.