Xylem and Phloem

Tissues in plants can be classified on the basis of the part they are present in or the kind of cells they contain. Largely, they are classified as simple (parenchyma, collenchyma, and sclerenchyma) and complex (xylem and phloem) cells. Here, we will explore the latter type.

Minerals and water are carried from the soil to the plants via xylem cells in plants. Salts in the soil are absorbed by roots and subsequently translocated upwards with water via the xylem. The stem, roots, and leaves all have linked xylem cells that form a conducting channel that reaches all sections of the plant. Ions are obtained by the root cells from the soil, resulting in a differential in ion concentration between the roots and the soil. As a result, the xylem receives constant water flow.

These two pathways are developed as autonomously coordinated directing cylinders: 

Xylem: 

• It moves water and minerals acquired from the dirt. 
• The tracheary components of xylem tissue are a group of specialised water-conducting cells.
• Formation of the xylem starts when the dividing cells of growing root and shoot tips, resulting in the formation of primary xylem tissues. 
• The secondary xylem makes up the majority of a mature stem or root in woody plants, and it develops when the plant grows in girth and produces a ring of new xylem around the primary xylem tissues.

Phloem: 

• Phloem is a kind of plant vascular tissue that transports foods produced in the leaves during photosynthesis to the rest of the plant.
• Phloem fibres, sieve elements, and phloem parenchyma cells are all types of specialised cells found in phloem tissues.
• All vascular plants, including seedless club mosses and ferns, contain phloem. 

Elements of xylem

1. Tracheids: Tracheids are made up of elongated cells with flat tapering ends xylem. The main function of tracheids is to provide a network of hollow connected cells for the transportation of water. They also provide mechanical support by developing various types of thickenings in their walls. 
2. Xylem vessels: Xylem vessels consist of dead cells. They are wider than tracheids. Their cell walls are hard, thick and lignified. The main function of xylem vessels is to allow free flow of water and minerals from roots to leaves.
3. Xylem parenchyma: They consist of living cells and act as the structural component of the xylem. The primary function of xylem parenchyma is to store food in the plant body. They also help in the conduction of water and minerals. 
4. Xylem fibres: They also act as the structural component of xylem tissues. They mainly function to support the plant.

Transport of food and different substances: 

Food is transported from the leaves to other plant parts via the vascular tissue, called phloem. The term “translocation” refers to the process of transferring food. Plants move carbohydrates from areas with abundant carbs, such as mature leaves, to parts where they are needed via the phloem. Photosynthesis produces energy-rich carbon molecules transferred out of the leaf to various organs and tissues.

The phloem also carries amino acids and other compounds. These compounds are primarily distributed to root, fruit, seed storage organs, and growth organs.

Food and other substances are transported in the sieve tubes in both upward and downward directions with the aid of nearby partner cells.

Material like sucrose is moved into phloem tissue utilising energy from ATP. 

This expands the solute strain of the tissue making water move into it. 

This tension moves the material in the phloem to tissues that have less strain.

Elements of Phloem 

1. Sieve tubes- Sieve tubes facilitate the exchange of material between the element cells. They help in the transport of sugar and nutrients in the plant body. 
2. Companion cells- Companion cells have a nucleus and dense cytoplasm. They act as a companion for the sieve tube
3. Phloem Parenchyma- The main function of phloem parenchyma is to provide mechanical strength to the plant.
4. Phloem Fibres- Phloem fibres provide support and stand to the plant and store compounds such as starch.

Conclusion :

Plants are multicellular eukaryotes with tissue systems made up of different cell types that perform specific tasks.  They are classified as simple and complex tissues. Complex plant tissue can be further classified as Xylem and phloem

Xylem tissue is responsible for transporting liquid materials throughout the plant.

Phloem tissue aids in the movement of food throughout the plant. Phloem fibres, sieve tubes, phloem parenchyma, and companion cells are some components of phloem.