Tissue culture plants
Table of Contents
Tissue culture plants
The body of all living beings is made up of cells.
All the biological activities of a single-celled organism take place inside one cell, such as Amoeba, Paramecium.
With the increase in division of labour, cells start gathering in groups and form tissue.
A group of cells whose origin, structure and function are similar is called tissue.
The study of tissues is called histology.
Importance of tissue
(i) To increase division of labor by tissue formation in multicellular organisms.
(i) Organs and organ systems are formed by groups of tissues.
(iii) The function of a cell is reduced by the tissue.
(iv) Increases survival in multicellular organisms.
Plant tissue
There are two types of plant tissues-
(1) Meristematic tissue
(2) Permanent tissue
Meristemic tissue:-
This tissue is made up of immature cells which have the ability to divide.
Dividing cells are oval or multinucleated whose cell membrane is made of cellulose.
Cell vacuole and intercellular spaces are not found in these.
These tissues are of three types depending on the condition.
(1) Apical meristems :-
It is found in the tip of the stem and root and grows in length.
(II) intercalary meristerns :-
It is found in between the permanent tissue.
This division is found in the base or joint part of the leaf. Increases length.
(iii) Lateral meristem: –
Occurs in the lateral parts of the root and stem and undergoes secondary growth.
This forms vascular tissues.
Due to this, the thickness of stem and root increases.
Parmanent tissue:-
By division of meristematic tissue, permanent tissue is formed which does not have the ability to divide.
These tissues are living or dead, thin walled or thick walled.
(a) Simple permanent tissue –
This tissue is made up of identical cells whose origin, structure and function are similar.
These are of three types-
(i) Parenchyma
(ii) Collenchyma
(iii) Sclerenchyma
(i) Parenchyma :-
Parenchyma cells are alive, oval, round, multi-lobed or irregular in shape.
Parenchyma tissue is found in various parts of the plant like root, stem, flower.
Function:-
(1) To collect food and water.
(2) The intercellular space present in tissues is important in gaseous exchange.
(3) Chloroplast is found in chlorenchyma which produces food through photosynthesis.
(4) Acts as protection for the plant in the form of epidermis.
(5) It stores excretory substances like gum, resins, tannins.
(ii) Collenchyma: –
Macro angle cells are long living with nucleus and contain vacuole.
This tissue is generally found under the epidermis of petiole, petiole and stem.
Pectin mixed cellulose is deposited in the intracellular spaces or on the granules of cells.
Function –
(1) It provides mechanical support to plants.
(2) It stores food.
(3) When chloroplast is found in it, it produces food.
(4) It increases organs.
(iii) Hard tissue (Sclerenchyma): –
It is a dead permanent tissue which has uniform accumulation of lignin around its cells.
Its cells are long and narrow and pointed at both the ends.
This tissue is generally found in the stem, veins of leaves, seed coat and coconut fiber.
Function :-
(1) It provides mechanical support to the plant.
(2) Forms a protective covering over the seeds.
(3) The root forms cork cells with growth in the stem.
(B) Complex permanent tissue: –
This tissue is more than two
Made up of different types of cells.
There are two types of these tissues.
(a) Xylem (b) Phloem.
(I) Xylem:-
It is a complex permanent tissue which transports mineral salts and water.
It contains four types of ingredients.
(1) Tracheids :–
These are long cylindrical dead cells whose walls contain accumulation of lignin.
Vessels are found in primary and secondary xylem.
Function:-
Providing mechanical support to the plant and transportation of water and mineral salts.
(2) Vessels: –
These are long tubular dead cells in which lignin is deposited in their walls.
Angiosperm is found in the primary and secondary xylem of the plant.
Function:-
Providing mechanical support to plants and transportation of water and mineral salts.
(3) Fibers: –
These are long, conical and dead cells containing lignin.
Function :–
They provide only mechanical support to the plant.
(4) Xylem Parenchyma:-
Living cells present in xylem
Function:-
Stores food.
(ii) Phloem:-
This complex permanent tissue which transports food substances.
It is called living vascular tissue.
It contains four types of components.
(i) Steve tubes:-
Sieve tubes are long, cylindrical cells located one above the other.
The dividing wall of the two cells is porous which is called a sieve strip.
Nucleus is not found in the sieve tube in the adult stage.
Function:-
Transports the food produced by the leaves.
(1) Companion cell:-
These are cells with moving wall which are present in sieve.
Located in the lateral part of the tubes.
Every co-cell is alive and contains a nucleus.
These Present only in phloem of angiosperms.
The chyme helps in the transportation of food substances through the tubes.
are thin and living cells which Located near the cells.
Function:-
Storing food items
Phloem fibre:-
This is the non-living part of phloem. these thick walled
Provide flexibility.
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Animal tissue
There are four types of tissues in animals.
(i) Epithelial tissue
(ii) Connective tissue
(iii) Muscular tissue
(iv) Nervous tissue
(i) Epithelial tissue:-
This tissue forms the outer and inner layers of the animal body.
The cells in this tissue remain so close that there is no intercellular space between them.
This tissue defense speeds up absorption, diffusion, excretion, exchange of gases.
And helps in secretion.
There are two types of epithelium.
(a) Simple epithelial tissue :–
It has only one surface of cells.
(b) Compound epithelial tissue: –
It contains many levels of cells.
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