Plant Tissues Structure And Function - Class 9 Science Free MCQ Practice

Collenchyma allows a plant's stem to bend easily without breaking.

It is typically found at the junction of the leaves and stems.

The key features of collenchyma include:

• Presence of elongated cells
• Strong, irregular cell walls

These characteristics provide extra support to the entire plant.

The husk of coconut is made up of sclerenchymatous tissue.

This tissue is found in the mesocarp (the middle layer) of the coconut fruit and produces coir, a well-known fibre used for making:

• Mats
• Ropes
• Cords
• Brushes

Sclerenchymatous tissue is also present in:

• Stems (around the vascular bundles)
• Roots
• Veins of leaves
• Hard coverings of seeds and nuts

The primary functions of sclerenchymatous tissue are:

• Mechanical support
• Protection
• Providing strength, rigidity, flexibility, and elasticity to the plant

Chlorenchyma is a type of parenchymatous tissue that performs photosynthesis. Here are the key points about this tissue:

• Storage Parenchyma: This type of parenchyma is responsible for storing nutrients and water in the stems and roots of plants.
• Chlorenchyma: When parenchyma cells contain chloroplasts with chlorophyll, they are known as chlorenchyma and are capable of photosynthesis.
• Aerenchyma: In aquatic plants, parenchyma contains large air spaces. This adaptation provides buoyancy, helping plants float and facilitating gas exchange.

Sclerenchyma cells are a type of permanent tissue found in plants. They serve to provide hardness and stiffness and are made up of dead cells. This tissue is located in various areas, including:

• Around vascular bundles in stems
• In the veins of leaves
• In the hard covering of seeds and nuts

For example, the husk of a coconut is primarily composed of sclerenchymatous tissue. The cells of sclerenchyma are long, narrow, and have thickened walls due to the presence of lignin.

Collenchyma: The cells possess walls that are thickened at the corners, primarily due to the deposition of pectin.

Sclerenchyma: In contrast, the walls of these cells are thickened due to the presence of lignin.