[Biology Class Notes] on Plant Tissues Pdf for Exam

On this page we will be discussing Plant Tissues, its Types, Properties, Examples and Classifications. But first learning about Plant Tissues in depth, let us talk about Cell and Tissues.

Cell: The basic structural and functional units of life is called a Cell

Tissue: A group of cells performing the same function and are similar in structure is called Tissues.

Plant Cell

Plants do not walk or move drastically; they are immobile. This is why they are given tissues that are built from dead cells; these cells provide the structural strength.

These plants face serious natural challenges like cyclones, floods, and strong winds.

Types of Tissues 

We can classify these tissues into two parts, Meristematic Tissues, and Permanent Tissues.

Meristematic Tissues

These tissues can further develop and have cells that keep on dividing.

These cell tissues exist in different regions of a plant structure. Based on the place where they are situated, we can classify the meristematic tissues into three kinds:

Permanent Tissues

The tissues whose cells cannot distribute themselves anymore but still can facilitate being protective, strengthening, and flexible to a plant or a tree are called permanent tissues.

We can classify these tissues into two different types, Simple Permanent Tissue and Complex Permanent Tissue.

Simple Permanent Tissue

Sclerenchyma: The tissues are dead and elongated and have lignin deposits on their cell wall. They are found in the seed coverings, nuts, veins of leaves, vascular tissues of stems and provide strength to a plant. They don’t contain any intercellular gaps.

Collenchyma: These tissues are made up of pectin and cellulose and are intercellular living cells with minuscule gaps between their structure. We can find them in the borderline regions of the stems and leaves; they offer flexibility to plants by providing them a structural framework and mechanical support.

Parenchyma: These tissues also contain living cells that are polygonal in shape with a large central vacuole. They have intercellular spaces between them. They are the developers of the pith and ground tissue in a plant. Their structure includes:

• Chloroplasts that are known as chlorenchyma help a plant in the photosynthesis process.

• Aerenchyma consists of huge air gaps which provide buoyancy to the plant.

• Some cells also act like storage cells for the plant where they store starch for the fruits and vegetables.

Complex Permanent Tissue

These tissues include:

Phloem: This tissue is the primary reason for proper flow of food throughout the plant. Xylem: This tissue is the primary reason for proper flow of water and other dissolved throughout the plant.

Protective Tissues

Some tissues are there to provide stronghold support to a plant. The most well known protective tissues are:

Cork: This tissue is entirely dead and is just there to protect the plants; their intercellular gaps are not there anymore, and their cell walls are impenetrable to gas and water molecules.  

Epidermis: This tissue creates the outer casting of the plant structure. It helps during the loss of water and gaseous exchange.

Properties of Meristematic Tissues

• We also call them Meristems.

• They are constantly dividing the cells in tissues inside the plant.

• They have very small vacuoles.

• The tissues have cells with very dense protoplasms.

• These tissues have the power of healing the wounds of plants.

•  They do not store food.

• They have a single, large and central nucleus.

• There is a high metabolic activity in them.

Properties of Permanent Tissues

• No vacuoles are present in the cells.

• They do not have the power of division.

• Their cells are suitably shaped and correctly assembled. 

• Their cell wall is comparatively thicker.

• Their nucleus is more prominent.

• Their cytoplasm is thick.

• They do not store food
  .

• There are sometimes intercellular spaces present between the cells.

Summary:

• The meristematic cells keep on bifurcating.

• Meristematic tissues based on their location are of three types namely; apical, lateral, and intercalary meristematic tissues.

• Permanent tissues are of two types: Simple and Complex.

• Dermal or protective tissues are simple tissues. They form the outer covering of plant parts such as the stem, roots, fruits, flowers etc. The epidermis and cork are two types of dermal tissues.

• The main function of the ground tissue is to provide support, strength, and flexibility to plants. The three types of ground tissues are; Parenchyma, Collenchyma, and Sclerenchyma.

• Vascular tissues are also called conducting tissues as they play an important role in the transportation of water and food in plants.

• Xylem is a water conducting tissue.

• Phloem is a food conducting tissue.