TISSUE SYSTEM OF FLOWERING PLANT(ANATOMY)

 

THE TISSUE SYSTEM:-

·         The tissue collectively form tissue system. Depending upon the location it has different structure and due to these it has different functions. It is of three types:-

1.      Epidermal tissue system

2.      Ground or Fundamental tissue system

3.      Vascular or Conducting tissue system

Epidermal Tissue System:-

·         It is the outermost covering of plant. It is consist of epidermal cells, stomata and epidermal appendages-The trichomes and hairs.

Ø  Epidermal cells:- It is parenchymatous cell of cytoplasmic cell wall which  forms continuous, elongated outermost layer of epidermal tissue system. Exteriorly epidermis has a waxy thick layer of cuticle which functions to prevent water loosing. Cuticles are absent in root of plant.

Ø  Stomata:- It is present in epidermis of leaves which functions to regulate the process of transpiration and gaseous exchanges. It is consist of two bean shaped guard cells. Guard cell contains chloroplast and its outer wall is thin while inner wall is thickened. In  Gases the guard cell converted into dumbbell shaped. The main function of guard cell is to regulate the opening and closing of stomata.

Ø  Epidermal Appendages:-  It is hair like projection and are of following type –

1.      Root hair:- it is unicellular elongation of epidermal cells. It helps to absorb the water and minerals from soil.

2.      Trichomes:- It is multicellular branched or unbranched epidermal hair cell. It may be soft or stiff and may perform secretary in nature. It is found in stem and perform transportation function.

The Ground Tissue System:-

·         It consists of simple tissues such as Parenchyma, Collenchyma and Sclerenchyma.

·         Parenchymatous present in cortex, pericycle, pith, medullary rays, in periphery of stem.

·         In leaves, the ground tissue consists of thin walled mesophyll cell containing chloroplast.  

The Vascular Tissue system:-  

·         It consists of complex tissues as xylem and phloem. Here xylem and phloem form vascular bundle. Vascular bundle may be are of two types.

1.      Open Vascular bundle:- The cambium is present between xylem and phloem in the dicotyledonous plant(Stem & leaves). Due to presence of cambium the bundle having ability to form secondary xylem and phloem tissues so this is called open type vascular bundles.

2.      Closed Vascular bundle:- The cambium is absent in the monocotyledonous plant(Stem & leaves) i.e. they don’t have ability to form secondary xylem and phloem. So it is called closed vascular bundle.

·         The arrangement of xylem and phloem either of radial or conjugant type.

1.      Radial:- The xylem and phloem are arranged in alternate manner in different radii, called radial arrangement. This arrangement is present in roots of plants.

2.      Conjoint:- The xylem and phloem are arranged at the same radius in vascular bundle, called conjoint arrangement. This arrangement is present in stem and leaves. In this arrangement phloem located exteriorly than xylem.

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