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Today we will discuss about the types of Plant Tissue System and their function, which is very tedious to remember.  So what we are going to do, we will try to understand the points in Telegraphic language, which we will elaborate in examination hall.  Now let us check out what are there in Plant tissue system

Plant Tissue system

Definition
Group of tissues performing a common function constitutes a tissue system.

 

There are three types of Tissue System in plant, which are in the following

  1. Epidermal tissue system

  2. Ground tissue system

  3. Vascular tissue system

 

 

EPIDERMAL TISSUE SYSTEM

 

Characteristic features

  1. Basically epidermal tissue system is present in root and stem
  2. In stem it is called epidermis, which is covered by cuticle. Cuticle is waxy in nature
  3. In root it is called epiblema, which is devoid of cuticle
  4. The epidermal outgrowths or hairs in stem are multicellular
  5. Stomata are present in leaves
  6. It is derived from Protoderm

Function

  1. Gives protection to the inner delicate tissues
  2. Chloroplast containing epidermal cells can synthesize food
  3. Cuticle checks the loss of water by transpiration

 

GROUND TISSUE SYSTEM

Characteristic features

  1. It contains hypodermis, which are found just below the epidermis
  2. It contains cortex, which are found just below the dermis
  3. It contains endodermis, which are found just below hypodermis, barrel shaped shape
  4. It contains pericycle, which are found just below hypodermis
  5. It contains medullary rays, which are found just below endodermis and between vascular tissues
  6. It contains pith, which are found in the innermost part of the stem or root
  7. It contains It contains mesophyll
  8. It is derived from ground meristem
  9. Casparian strips of suberin are found sometime in the endodermis of root
  10. The pericycle, the medullary rays or conjunctive tissues, pith and vascular bundle together known as stele or central cylinder

Function

  1. Protection of vascular tissues
  2. Storage of reserve food, excretory substances, and secretory substances
  3. Provides rigidity to the plants

 

 

VASCULAR TISSUE SYSTEM

Characteristic features

  1. It is represented by xylem and phloem
  2. The strand of xylem and phloem is called vascular bundle or fascicles
  3. It is the derivatives of procambium
  4. A vascular bundle may contain either only xylem or only phloem or both. According to the relative position of xylem and phloem the bundles can be distinguished into three types.
  1. Conjoint Bundle
  2. Radial Bundle
  3. Concentric Bundle

Conjoint Bundle

In conjoint Bundle xylem and phloem occur in the same bundle along the same radius.

Conjoint Bundle is of two types

Collateral:  When only one set of xylem and one set of phloem are present in the bundle

Open Type:  When cambium is present Eg.  Dicot Stem (Sunflower)

Closed Type:  When cambium is absent Eg. Monocot stem (Maize)

Bicollateral:  When vascular bundle has one set of xylem, two sets of cambium and two sets of phloem                       Eg.  Cucurbita

The conjoint bundles are seen only in leaves and stem

Radial Bundle

Here xylem and phloem occur in separate bundles, alternately.  Eg.  In Dicot and Monocot Root

Concentric Bundle

Here xylem and phloem occur in the same bundle surrounding each other

Hadrocentric or Amphicribal:  When xylem in the centre surrounded by phloem Eg. Selaginella

Amphivasal or Hadrocentric:  When phloem in the centre surrounded by xylem  Eg. Yucca

N.B.

Endarch is the mode of arrangement where the protoxylem is directed towards the centre and metaxylem towards the periphery.  Eg. Stem of flowering plants

Exarch is the mode of arrangement where the protoxylem is directed towards the periphery and metaxylem towards the centre.  Eg. In root.

 

Internal Structure of Young Dicot Stem of Sunflower (Helianthus annus)

Transverse section of the stem comprises the following features:

A) Epidermal Tissue System contains following items

1)  It is the outermost layer

2)  Single layered

3)  Contains Parenchymatous Tissue

4)  No intercellular spaces

5)  Outer wall consists of cuticle to check transpiration

6)   Hairs multicellular are found

 

B) Ground Tissue System contains following items

1)  Cortex consists of Hypodermis few layer of collenchymatous tissue and below hypodermis few layers of parenchymatous tissue

  1. Endodermis contains wavy barrel shaped starch containing cell, hence it called starch sheath
  2. Pericycle contains alternate patches of sclerenchymatous and parenchymatous tissues
  3. Medullary rays contains compressed parenchymatous tissue without intercellular spaces
  4. Pith contains large parenchymatous tissue with intercellular cells


C) Vascular Tissue System
contains following items

  1. Collateral
  2. Open type
  3. Xylem is endarch

 

Internal Structure of Young Dicot root of Gram (Ceicer arietinum)

 

Transverse section of the root comprises the following features:

A) Epidermal Tissue System contains following items

1)  It is the outermost layer called as Epiblema

2)  Single layered barrel shaped cells

3)  Contains Parenchymatous Tissue

4)  No intercellular spaces

5)  No cuticle

6)   Hairs single cellular are found

 

  1. B) Ground Tissue System contains following items

1)  No Hypodermis

2)  Cortex contains many layered parenchymatous cells with intercellular spaces

  1. Endodermis contains barrel shaped parenchymatous tissue with casparian strips
  2. Pericycle contains sclerenchymatous tissue
  3. No Medullary rays
  4. No Pith

 

  1. C) Vascular Tissue System contains following items
  2. Radial
  3. Tetrarch
  4. Exarch

 

Internal Structure of Young Dicot leaf of Mango (Mangifera indica)

Transverse section of the stem comprises the following features:

A) Epidermal Tissue System contains following items

1)  It is the outermost layer

2)  Barrel shaped cells form upper and lower epidermis

3)  Contains Parenchymatous Tissue

4)  No intercellular spaces

5)  Stomata are present


B) Ground Tissue System
contains following items

1)  Mesophyll tissue

It contains two layered tubular chloroplast containing cells called Palisade Parenchyma

It also contained loosely arranged round to oval shaped chloroplast containing cells called Spongy Parenchyma

C) Vascular Tissue System contains following items

  1. Mesarch

Diagram of Cross Section of Dicot leaf

 

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PpG

 

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Hi viewers My name is Partha Pratim Goswami, (PpG) I am a teacher by profession. I have been teaching biology, chemistry and physics, sometimes mathematics also for last sixteen years. I would like to share my entire experience with all the viewers across the world through YouTube, which I think is an amazing platform to share all my experiences.

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