Cell: A cell is the basic structural and functional unit of a living organism. Example: Nerve cell.
Tissue: A tissue is a group of cells having a common origin, similar structure and function and held together by a cementing substance. Example: Connective tissue.
Organ: Different types of tissues working together and contributing to some specific function inside the body constitute an organ. Example: Stomach.
Organ system: Different organs coordinate to perform a specific life process and form an organ system. Example: Digestive system.
Organism: Various organ systems working simultaneously together constitute an organism. Example: Plants. In this article we are going to learn only about Phloem.
Classification of plant tissues
- MERISTEMATIC TISSUE
- PERMANENT TISSUE
Types of Permanent Tissue
- Protective tissue
- Supporting tissue
- Conducting tissue
Conducting tissue
Conducting tissues are also called vascular tissue. Conducting tissues are Present in the stem, roots and leaves. Conducting tissue Provide a passage for water and dissolved materials to move up and down in the plant body.
Types of Conducting tissue:
- Xylem
- Phloem
Phloem
| CHARACTERISTICS | Complex permanent tissue. |
| LOCATION | Lies just beneath the bark of the tree. |
| FUNCTION | Provides a passage for the downward movement of food manufactured in the leaves to various parts of the plant. |
Components of Phloem
- Sieve tubes
- Companion Cells
- Phloem fibres
- Phloem parenchyma
Sieve tubes
| CHARACTERISTICS | Tubular cells with perforated walls and arranged end to end. |
| FUNCTION | Translocation of organic substances through perforated walls from one adjacent cell to another. |
Companion cells
| CHARACTERISTICS | Cells are living and keep their nuclei and other organelles throughout their life. |
| FUNCTION | Help to control the activity of sieve tube elements. |
Phloem fibres
| CHARACTERISTICS | 1. Elongated, tapering and dead cells. 2. Cell walls are thickened. |
| LOCATION | Found particularly in the stem. |
| FUNCTION | Provide mechanical strength to the plant. |
Phloem parenchyma
| CHARACTERISTICS | Cells are alive and filled with cytoplasm. |
| FUNCTION | Transports food i.e. sugars and amino acids from the leaves to other non-green parts of the plants, such as growing stems and roots. |
YOU MAY READ Xylem
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