what is permanent tissues ?
Answers
Answer:
Permanent tissues are a group of living or dead cells which are formed by meristematic tissues that have lost their ability to divide. That is, these tissues have undergone differentiation and are incapable of meristematic activities.
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Answer:
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Explanation:
Permanent Tissue:
The tissues that are completely grown and have lost the ability of division are known as permanent tissues. The meristematic tissues divide and differentiate to form the permanent tissues.
Types of Permanent Tissue:
Simple Permanent Tissue:
These are also known as homogenous tissues. They are made up of a single cell type, usually with the same origin, structure, and function.
Simple permanent tissue is further classified into three types:
Parenchyma:
The cells have an oval or round shape.
The cell wall is made up of hemicellulose or cellulose.
The cell is thin-walled.
The cells have vacuoles and very small nucleus.
It is found in all parts of the plant.
The protoplasm is living and dense.
Collenchyma:
Cells are long and thick-walled.
The cell wall is made up of cellulose and pectin.
It is the only tissue with the highest refractive index due to the presence of pectin.
It is found in the epidermis and the vascular bundle of dicot leaf.
The amount of chloroplast is less in the cells.
The cells have no intercellular spaces.
Sclerenchyma:
These are dead tissues, very hard and rigid in texture.
Cells are thick-walled with various size and shapes.
These provide mechanical support and rigidity to the plant.
Complex permanent Tissue:
The complex tissues are made up of various types of cells carrying out distinct functions and are of two types:
Xylem:
It transports water and nutrients from the roots to the leaves of the plant.
It provides support to the plants.
It is divided into-tracheids, vessels, xylem fiber, and xylem parenchyma.
Phloem:
It translocates the prepared organic food from the leaves to different parts of the plant.
It is also known as bast.
It is composed of sieve tubes, companion cells, phloem parenchyma, and phloem fibres.
Special Tissues:
They are modified structurally to carry out functions secretory in nature and are of two types:
Laticiferous Tissues:
The plant tissues have latex.
They originate from the meristematic tissues and mature with other tissues.
The cells are elongated, thin-walled and multinucleated.
Observed in a large number of families such as Euphorbiaceae, Apocynaceae, Compositate, etc.
Glandular Tissues
They possess various glands, that secrete oil, resins, tannin, mucilage, etc.
The gland is situated on the epidermis
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