ICSE Class 9 Biology Plant and Animal Tissues 1 – Plant Tissues

Summary

This script delves into the fascinating world of plant tissues, highlighting the crucial roles of meristematic and permanent tissues in plant growth and structure. Meristematic tissues, responsible for plant growth at the tips of stems and roots, differentiate into permanent tissues that can be simple or complex. Simple permanent tissues like parenchyma and collenchyma provide support and flexibility, while complex tissues like xylem and phloem facilitate transport of water, minerals, and sugars. Protective tissues, such as the epidermis and cork, shield plants from the environment, ensuring their survival and adaptation.

Takeaways

• 🌱 Meristematic tissues are responsible for plant growth, rapidly dividing at the tips of stems and roots.
• 📏 Meristematic tissues are classified into apical, lateral, and intercalary, each with specific roles in plant structure and growth.
• 🔄 Differentiation is the process where meristematic cells lose their ability to divide and transform into permanent tissues.
• 🌿 Parenchyma is a type of simple permanent tissue that forms the ground tissue in plants and is involved in photosynthesis and food storage.
• 🌻 Collenchyma is another simple permanent tissue that provides mechanical support and flexibility in plants.
• 🌳 Sclerenchyma is composed of dead cells with lignin, offering strength to the plant's vascular tissues and coverings.
• 🌲 Xylem is a complex permanent tissue that includes tracheids, vessels, and fibers, essential for water and mineral transport.
• 🍬 Phloem is another complex permanent tissue with sieve tubes, companion cells, and fibers, responsible for food transport and storage.
• 🛡 Protective tissues such as epidermis and cork shield the plant from the environment and facilitate gaseous exchange through stomata.
• 🌾 Epidermal cells in roots have hair-like structures for absorption, and as plants age, the cork layer provides a secondary protective barrier.

Q & A

What is the basic unit of structure and function in plants?

The basic unit of structure and function in plants is the cell, which can form tissues when similar cells work together.

Why are some plant tissues composed of dead cells?

Some plant tissues are composed of dead cells to provide mechanical strength, as plants are stationary and require structural support.

What is the role of meristematic tissue in plant growth?

Meristematic tissue is responsible for plant growth as it consists of rapidly dividing cells that increase the length at the tips of stems and roots.

How are meristematic tissues classified based on their location in the plant?

Meristematic tissues are classified as apical, lateral, and intercalary based on their location in the plant, affecting different aspects of growth such as length and girth.

What happens to meristematic cells as they age?

As meristematic cells age, they lose the capacity to divide and transform into permanent tissues through a process called differentiation.

What is the function of parenchyma tissue in plants?

Parenchyma tissue serves as the ground tissue in the central cortex and peripheral parts of stems and roots, and in leaves, it contains chloroplasts for photosynthesis.

What is the primary function of collenchyma tissue?

Collenchyma tissue provides mechanical support and flexibility in plants, with its cells having irregularly thickened cell walls at the corners.

How does sclerenchyma tissue contribute to the strength of a plant?

Sclerenchyma tissue contributes to the strength of a plant by consisting of long, narrow, dead cells with lignin deposited in their cell walls, found in vascular tissues and covering seeds and nuts.

What are the two types of complex permanent tissues in plants and what do they do?

The two types of complex permanent tissues are xylem and phloem. Xylem transports water and minerals, while phloem transports sugars or food from the leaves to other parts of the plant.

What is the role of the epidermis in plant protection?

The epidermis is the outermost protective layer of fruits, stems, and leaves, serving to protect the plant and facilitate gaseous exchange through stomata.

What is the function of the periderm in older roots and stems?

The periderm, formed by secondary meristems, replaces the outer protective tissue in older roots and stems, providing a waterproof barrier that is impermeable to gases and water.