TYPES OF TISSUES IN PLANTS

PLANT TISSUES

Plants perform several life processes like growth, respiration, excretion, photosynthesis.

Plant cell has a cell wall. The group of cells that perform a similar function and are similar in structure is known as tissue.

There are basically four types of tissues in plants

  • MERISTEMATIC TISSUES
  • DERMAL TISSUES
  • GROUND TISSUES
  • VASCULAR TISSUES

1.MERISTEMATIC TISSUES

  • Tissues that brings about overall growth and repair in a plant is the meristematic tissue.
  • It brings about the growth in the plant body.
  • This tissue is again classified into three types
  1. Apical Meristematic tissue
  2. Lateral Meristematic tissue
  3. Intercalary Meristematic tissue.

APICAL MERISTEMATIC TISSUE

  • The tissues that helps in the growth of the plant is called Apical Meristematic.
  • This tissue is present at the growing tips, sides and in between layers of other tissues.
  • E.g., root tip, shoot tip

LATERAL MERISTEMATIC TISSUE

  • Tissue that gives rise to the growth in girth of the steam is called Lateral Meristematic.
  • This tissue is present at the edges in a lateral manner.

INTERCALARY MERISTEMATIC TISSUE

  • Tissue that present at the branching takes place or a leaf or a flower stalk grows are known as intercalary Meristematic.

2.DERMAL TISSUES

  • Dermal tissue is usually consisting of a single layer of tissue showing variation in the types of cells
  • The tissue that protects the plants from water loss, mechanical damage and invasion by disease causing organisms is the dermal tissue.
  • It secrets various excretory products.
  • On the basis of their location and function dermal tissues are studied as three different types.
  1. Epidermis (outermost layer)
  2. Mesodermis (middle layer)
  3. Endodermis (innermost layer)
  • The wall of the cells of dermal tissue are thicker as compared to the cells of Meristematic tissues.
  • In desert plants it may be even more thick and waxy. Small pores are seen in the epidermis of the leaf, called stomata.
  • They are enclosed by two kidney shaped cells, called guard cells.
  • Cells of the roots have long hair like parts, called root hair.

FUNCTION OF DERMAL TISSUE

  • Stomata and root hair also dermal tissues that are essential for gaseous exchange and transpiration as well as absorption of water and minerals respectively.
  • In big trees the dermal tissues from several layers above the epidermis it is called bark.

3.GROUND TISSUES

  • Tissues that forms the bulk of the plant body is called ground tissue. It helps in storing food and give physical support to the plant.
  • There are mainly three types of ground tissues. They are
  1. PARENCHYMA
  2. COLLENCHYMA
  3. SCLERENCHYMA

PARENCHYMA

  • The cell of the Parenchyma is soft, thin walled and loosely packed.
  • Parenchyma again classified as three types
  1. CHLORENCHYMA
  2. AERENCHYMA
  3. STORAGE TISSUE

CHLORENCHYMA

  • The Parenchyma which contains a chloroplast is known as Chlorenchyma.
  • They perform photosynthesis.
  • E.g., Palisade Parenchyma, spongy Parenchyma.

AERENCHYMA

  • The Parenchyma which contains large air cavities or space is called Aerenchyma.
  • They provide buoyancy.
  • E.g., Cortex of water plants like Hydrilla, Eichornia.

STORAGE TISSUE

  • The Parenchyma which stores water, food or waste materials is called Storage Tissue.
  • The help in storage of reserve food.
  • E.g., Endodermis of seeds.

COLLENCHYMA

  • Collenchyma tissues have thicker walled, longer cells compared to Parenchyma.
  • This gives mechanical support to plant.
  • Intercellular space is present.

SCLERENCHYMA

  • In the Sclerenchyma the cells are thick walled and compactly arranged with nearly no space between them.
  • They give mechanical strength to the plant.

4.VASCULAR TISSUES

  • Any tissues which contain vessels through which fluids are passed is called a Vascular tissue.
  • Vascular tissue gives mechanical support to the plant as well.
  • The Vascular tissues are again classified as two types
  1. XYLEM
  2. PHLOEM

XYLEM 

  • Xylem conducts water and material salt from the roots to the leaves.
  • Tracheid, vessels, fibers and Parenchyma are consists of Xylem
  • In Xylem only Xylem parenchyma is living.

PHLOEM

  • Phloem conducts food from the leaves to the growing parts of the plants.
  • The Phloem consists of sieve cells, sieve tubes, companion cells, fibers and Parenchyma.
  • Only phloem fibers are non-living.

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