Simple Permanent Tissue
These tissues consist of a single type of cell, mainly originating from the same source and having similar structure and functions. They are also called homogeneous tissues. Simple permanent tissue is classified into three types that is as follows:
Parenchyma
Parenchyma cells have thin cell wall composed of hemicellulose or cellulose and a large central vacuole. These cells are involved in photosynthesis, gas exchange and nutrient storage.
Types of Parenchyma
The parenchyma is divided into two types as follows:
- Chlorenchyma: It contains chlorophyll and helps in photosynthesis is known as chlorenchyma
- Aerenchyma: It contains air cavities and is present in aquatic plants is known as aerenchyma. It provides buoyancy to aquatic plants. They help in the formation of the anaerobic rhizosphere in anaerobic soil.
Collenchyma
These tissues consists of living and elongated cells which are irregularly thickened at the corners due to mechanical stress on plants. They provide flexibility and mechanical support to the plant. It helps various parts of plants to bend without breaking. They are found under the epidermis and in the vascular bundle of dicot leaf. They lack intercellular spaces. They produce new cells and help in the elongation of the stem. They are mostly found in monocot plants such as palm, coconut, etc. Collenchyma contains cellulose, hemicelluloses, and pectic materials. It may or may not contain a chloroplasts and perform photosynthesis and store food.
Types of Collenchyma
The collenchyma is divided into four types as follows:
- Tangential Collenchyma: In this collenchyma cells are thickened at the tangential part of the cell wall and are arranged into lined-up rows.
- Lacunar Collenchyma: In this collenchyma, they have space within the cells.
- Angular Collenchyma: In this collenchyma, the intercellular contact points are thickened.
- Annular Collenchyma: In this collenchyma, cell walls are thickened uniformly.
Sclerenchyma
These tissues are made up of long and narrow dead cells and lack inter-cellular space. They have thick, lignified cell walls, thereby it provides strength and durability to plant structure. Sclerenchyma cells offer rigidity, structural support and protection. These are present in the stem, around the vascular bundle, in the veins of leaves, and in the hard covering of seeds and nuts.
Types of Sclerenchyma
The sclerenchyma is divided into two types as follows:
- Fiber: They have long cells which provide strength to the plant. They are often found in bundles or strands and present in the stem, the roots, and the vascular bundles of leaves. They are mainly found in clusters, clumps, or patches.
- Sclereids: They are present in different shapes and are found in tissue such as the periderm, cortex, pith, xylem, and phloem. They are present in various parts of the plants like in the outer covering of nuts and seeds. Example: The grainy texture of pears and guavas.
Permanent Tissues – Diagram, Types Notes Biology Class 9
Permanent tissues are a type of plant tissue that has completed its growth and differentiation. They remain in a specialized state throughout the plant’s life. These tissues perform specific functions and are responsible for the overall structural growth and function of the plant. There are three main types of permanent tissues in plants: Parenchyma, Collenchyma, and Sclerenchyma.
Table of Content
- What is Permanent Tissue?
- Types of Permanet Tissue
- Simple Permanent Tissue
- Difference Between Parenchyma, Collenchyma, and Sclerenchyma
- Complex Permanent Tissue
- Secretory Tissues
- FAQs on Permanent Tissues