Plant Tissue System Explained: Types, Functions and Diagrams

Meristematic tissue consists of cells that retain the ability to divide continuously. These cells are typically small, with dense cytoplasm and a prominent nucleus. They have thin cell walls and very little to no intercellular spaces. When someone asks, “What is meristematic tissue?”, the simplest answer is that it is the tissue responsible for primary (lengthwise) and secondary (widthwise) growth.

Meristematic tissues can be categorised based on their position in the plant:

• Apical Meristem: Present at the tips (apex) of roots and shoots, causing the plant to grow longer.

• Lateral Meristem: Found along the sides of stems and roots, enabling the plant to grow wider or thicker.

• Intercalary Meristem: Located at the internodes or the base of leaves, facilitating lengthening between mature tissues (especially in grasses).

Over time, meristematic cells differentiate and become part of permanent tissues—this is a process called “differentiation.”

For more insights on these actively dividing tissues, explore Meristematic Tissues in detail.

Permanent Tissues

Permanent tissues arise when meristematic cells lose the capacity to divide and instead specialise for various functions such as support, storage, and transport. They are broadly divided into simple permanent tissues and complex permanent tissues.

Simple Permanent Tissues

1. Parenchyma

• Usually composed of living, thin-walled cells.

• Often polygonal in shape with large intercellular spaces.

• Special types include:

• Chlorenchyma: Contains chloroplasts; vital for photosynthesis.

• Aerenchyma: Contains large air spaces, providing buoyancy (often found in aquatic plants).

2. Collenchyma

• Consists of elongated living cells with thickened corners due to pectin and cellulose deposits.

• Offers flexibility and mechanical support, particularly in the stems and leaf stalks.

3. Sclerenchyma

• Composed of long, dead cells with lignified cell walls and negligible intercellular spaces.

• Provides significant strength and rigidity (seen in the shells of nuts and the gritty texture in pears).

Complex Permanent Tissues

Complex permanent tissues are made up of more than one type of cell, working together to perform a common function—primarily conduction.

1. Xylem

• Transports water and minerals from the roots to other plant parts.

• Comprises tracheids, vessels, xylem parenchyma, and xylem fibres.

• Lignin in xylem elements adds strength, helping the plant stay upright.

2. Phloem

• Conducts prepared food from leaves (or storage tissues) to all other parts.

• Consists of sieve tubes, companion cells, phloem parenchyma, and phloem fibres.

For a more focused comparison, refer to Difference Between Xylem and Phloem.

Protective Tissues

Protective tissues shield the plant’s outer surfaces from water loss, mechanical injury, and infection.

1. Epidermis

• The single outer layer covers leaves, stems, and roots.

• May be punctuated by stomata that facilitate gas exchange and transpiration.

2. Cork (Phellem)

• Substitutes the epidermis in mature roots and stems.

• Composed of tightly packed, dead cells.

• Walls contain suberin, making them impervious to water and gases.

Quick Mnemonic for Plant Tissues

Here’s a fun mnemonic for the main tissues: “My Plants Grow Pretty Constantly.”

• My – Meristematic

• Plants – Parenchyma

• Grow – Ground tissues (Collenchyma, Sclerenchyma)

• Pretty – Phloem

• Constantly – Complex tissue (Xylem and others)

This mnemonic reminds you that meristematic tissues are responsible for growth, and permanent tissues come in various types (simple and complex).

Short Quiz for Practice

Here’s a quick quiz you can use for plant tissue class 9 mcq practice:

1. Which tissue is responsible for the increase in the thickness of the stem?
A. Apical meristem
B. Lateral meristem
C. Intercalary meristem
D. Epidermis

2. What type of tissue is present in the husk of a coconut?
A. Parenchyma
B. Collenchyma
C. Sclerenchyma
D. Phloem

3. Which tissue in plants helps in the transport of food?
A. Xylem
B. Phloem
C. Sclerenchyma
D. Parenchyma

Quiz Answers

1. B – Lateral meristem

2. C – Sclerenchyma

3. B – Phloem

Plant Tissue Class 9 Questions and Answers

1. Explain the main features of meristematic tissue.

Students should highlight that meristematic tissue has actively dividing cells, thin cell walls, dense cytoplasm, and large nuclei.

2. Why is the xylem called a complex permanent tissue?

Expected answer: Xylem is composed of different types of cells—tracheids, vessels, xylem fibres, and xylem parenchyma—all collaborating for water transport and support.

3. Differentiate between parenchyma and sclerenchyma.

Parenchyma cells generally live with thin walls and intercellular spaces, whereas sclerenchyma cells are dead, heavily lignified, and provide structural strength.

For further clarity on specific plant tissue elements, check out Difference Between Tracheids and Vessels