Vascular Tissue : Xylem and Phloem

Xylem and Phloem represent two distinct types of vascular tissues primarily engaged in transportation. The xylem exhibits unidirectional movement, whereas the phloem demonstrates bidirectional movement. Vascular tissues in plants are complex conducting tissues composed of various cell types and elements. Xylem and Phloem are vascular plant tissues.

Xylem plays a crucial role in transporting minerals and water from the soil to the plants. On the other hand, phloem is a vascular tissue responsible for distributing sugars and nutrients produced in the shoot of plants. In this article, we will read about Vascular tissues- xylem and phloem, their functions and differences.

What is Vascular Tissue?

Vascular tissues in higher plants are complex conducting structures composed of various cell types and elements. Xylem and Phloem are the two main components of plant vascular tissue. These tissues play a crucial role in transporting water and nutrients within the plant. Moreover, vascular tissues are linked to two meristems: cork cambium and vascular cambium. These are responsible for secondary growth in plants. The collective action of the xylem, phloem, cork cambium, and vascular cambium forms the vascular tissue system of plants.

An Overview of Vascular Tissue

The following is an overview of vascular tissue:

Type	Vascular Tissues
Nature	Heterogeneous
Cell	Parenchyma and sclerenchyma
Location	Vascular regions of plant
Function	Translocation
Example	Xylem and phloem

What is Xylem?

The xylem is a vascular tissue in terrestrial plants mainly responsible for water distribution and mineral absorption by the roots. It is a crucial part of wood. The tracheary components of xylem tissue are specialized cells that conduct water. Xylem formation begins when cells divide in growing roots and shoot tips, leading to the creation of primary xylem tissues. In woody plants, the majority of a mature stem or root is composed of a secondary xylem. The production of a ring of new xylem around the primary xylem makes the plant wider.

Xylem Elements

the following are the elements of xylem:

• Tracheids: Tracheids are elongated cells with flat, tapering ends in the xylem. The primary function of tracheids is to create a network of hollow, connected cells for the transport of water. Additionally, it provides mechanical support.
• Xylem Vessels: Xylem vessels are composed of dead cells that are wider than tracheids. The cell walls of vessels are hard, thick and lignified. It allows the free flow of water and minerals from roots to leaves.
• Xylem Parenchyma: These cells are living and serve as the structural component of the xylem. The xylem parenchyma stores food in the plant body. They also assist in the water and mineral conduction.
• Xylem Fibres: Xylem fibres primarily function to support the plant.

What is Phloem?

The phloem is a vascular tissue which is mainly responsible for the distribution of food and minerals throughout the plant. The phloem mainly distributes sugars and nutrients produced in the leaves to other parts of the plant. It helps transport food made during photosynthesis to different plant areas. Phloem tissues include specialized cells like phloem fibres, sieve elements and phloem parenchyma cells. All vascular plants have phloem.

Phloem Elements

The elements of phloem are as follows:

• Sieve Tubes: Sieve tubes assist in material exchange between cells. They play a role in transporting sugar and nutrients throughout the plant.
• Companion Cells: Companion cells are equipped with a nucleus and dense cytoplasm and serve as companions for the sieve tube.
• Phloem Parenchyma: The primary function of phloem parenchyma is to offer mechanical strength to the plant.
• Phloem Fibres: Phloem fibres provide support to the plant and act as a structural element. It stores compounds like starch.

Functions of Xylem and Phloem

The following are the functions of xylem and phloem:

Xylem

• The xylem is mainly responsible for water distribution
• It is responsible for mineral absorption by the roots

Phloem

• Food moves to other parts of the plant through the phloem. The process of transferring food is known as “translocation.” Plants use the phloem to transport carbohydrates to the parts of the plant where needed.
• In addition to carbohydrates, it also translocates amino acids and other compounds and distributes them primarily to roots, fruit, seeds, storage organs and growth organs. Sieve tubes with the help of nearby partner cells transport food and substances both upward and downward.
• The movement of materials like sucrose into the phloem tissue requires energy from ATP. This process increases the solute pressure in the tissue wich causes water to move into it. The resulting tension helps move the material in the phloem to tissues with lower pressure.

Difference between Xylem and Phloem

Xylem and phloem is the vascular tissue found in plants. The main difference between the xylem and phloem is xylem transports water and minerals and the phloem transports food and nutrients to different parts of the plant.

Based on other characteristics the difference is as follows:

Characteristic	Xylem	Phloem
Transporting Material	Water and minerals	Food and nutrients
Elements	Tracheids, xylem vessels, xylem parenchyma, and xylem fibres.	Phloem fibres, sieve elements, and phloem parenchyma cells
Movement	Unidirectional	Bidirectional
Position	Inside the vascular bundle towards the center.	Outside the vascular bundle

Vascular Cambium

Vascular cambium is a tissue found in plant roots and stems that controls secondary growth. This tissue is found in the space between the plant’s phloem and xylem. Being a secondary meristem, the vascular cambium forms after the tissues of the main plant body have undergone differentiation. The vascular cambium is the primary growth tissue in the stems and roots of many plants, including

• Dicots, which include oak trees and buttercups.
• Pine trees and other gymnosperms.
• Some other types of vascular plants.

Cork Cambium

Cork cambium is a tissue found in the epidermis in vascular plants. Cork and phelloderm cells are produced by a single-cell layer of cells. It can be discovered in the trunks and stems of woody plants, including gymnosperms and angiosperms. The phellogen is another name for the cork cambium. It is the source of the periderm, a protective tissue that grows in place of the epidermis when the parent plant body’s epidermis is eventually destroyed by secondary growth.

Conclusion – Vascular Tissue: Xylem and Phloem

Plant tissues are classified into simple and complex. Complex plant tissues are further categorized into xylem and phloem. The xylem transports water and other liquids throughout the plant while the phloem aids in moving food and minerals. All vascular plants have phloem. Both xylem and phloem are essential for the survival of plants. Secondary meristems which are formed in stems and roots includes cork cambium and vascular cambium. Cork cambium is a lateral meristem and vascular cambium is a cylindrical secondary meristem.

FAQs on Vascular Tissue

What is the Difference between the Xylem and the Phloem functioning?

Xylem transports water and minerals and Phloem transports food and nutrients to different parts of the plant.

What is the Xylem and its Function?

The xylem is a vascular tissue in terrestrial plants. It is responsible for water distribution and mineral absorption by the roots.

What is the Function of Phloem?

The phloem distributes sugars and nutrients produced in the leaves to other parts of the plant.

How are the Xylem and Phloem Different and Similar?

Difference: The cells in the Xylem are dead and the phloem is made of living cells. Similarities: The xylem and phloem both are involved in the movement of various substances through the plant.

Does Xylem carry Water?

Yes, xylem transports water. Plant vascular tissue called xylem is responsible for carrying nutrients and water from the roots to the remaining parts of the plant. Moreover, xylem offers structural support.

What are the 4 Types of Phloem?

Four types of phloem are sieve tubes, phloem parenchyma, phloem fibres and companion cells.

Where is Phloem Located?

Phloem is located in the center of the vascular bundle.