Parenchyma is a simple permanent tissue that makes a major part of ground tissues in flowers, in which other tissues like vascular tissues are embedded. Parenchyma is non-vascular and composed of simple, living, and undifferentiated cells, which can be changed to carry out many functions.
The various features of parenchyma are:
- It is a living cell
- It has a prominent nucleus and protoplast
- This tissue forms the major component within various organs of plants and is present in all of them, ie., roots, stems, leaves, flowers, fruits, and seeds. It forms the main bulk of the plant body.
- The cells of the parenchyma are called the parenchymatous cells. The parenchymatous cells do not lose their protoplasm (the living contents of a cell) during their maturation hence, they are living cells.
- The cells of the parenchyma are generally isodiametric. Iso means equal and ‘diametric refers to diameter. The parenchymatous cells have nearly equal diameters in different planes.
- These cells may be spherical, oval, round, polygonal, or elongated in shape (polygonal cells have many sides and elongated cells are longer in shape).
- The parenchymatous cells are thin-walled. Their cell walls are made up of cellulose which is a major structural component of the cell walls of plants.
- Cells in the parenchyma tissue may either be closely packed with no intercellular spaces or have small intercellular spaces.
Functions of Parenchyma Cells:
Parenchyma performs various functions like
(a) Storage of food: One of the main functions of this tissue is storage of food. The parenchymatous cells store various food materials like carbohydrates, oils, fats, proteins, etc.
(b) Photosynthesis: Some parenchymatous cells develop chloroplasts in them and perform photosynthesis, ie., synthesis of food from inorganic substances in presence of light energy. Chloroplasts containing parenchyma is called the chlorenchyma.
(c) Secretion: Some parenchymatous cells secrete the substances like resin, nectar, oil, etc. These cells lie in the resin ducts and other secretory structures and help in the release of their products from the plant body also.
|Aerenchyma: Aerenchyma is a type of parenchyma found in hydrophytes, i.e., plants living in water bodies. This is a specialized tissue in which large air cavities are formed by the cells of these tissues. These air cavities are filled with air. The plants become buoyant due to the presence of air which helps them to float and it facilitates the gaseous exchange also.|