Meristematic tissues | Tissues | Biology class 9 | Khan Academy

Summary

This educational video delves into the fascinating world of plant tissues, contrasting them with animal tissues and emphasizing their unique adaptations for stationary life. It explains the concept of tissues as groups of cells with similar structures that collaborate to perform specific functions. The video focuses on meristematic tissues, which are cells that actively divide, and permanent tissues, which do not. It highlights the process of differentiation, where meristematic cells give rise to specialized permanent tissues. The video also illustrates where these tissues are located in a plant, such as apical, lateral, and intercalary meristems, and how they contribute to the plant's growth and development.

Takeaways

• 🌿 Tissues are groups of cells with similar structure that work together to perform specific functions in living organisms.
• 🌱 Plant tissues are fundamentally divided into two types: meristematic (dividing) tissues and permanent (non-dividing) tissues.
• 🌳 Permanent tissues are more abundant in plants than meristematic tissues because they originate from the division of meristematic cells.
• 📚 The process of forming specialized tissues from meristematic tissue is called differentiation, a key concept in biology.
• 🔬 Meristematic cells have thin cell walls, dense cytoplasm, prominent nuclei, and lack vacuoles, which allows for rapid cell division.
• 🌱 Meristematic tissues are found in growing regions of plants, such as shoot tips, root tips, and areas where new branches and leaves form.
• 🌳 Apical meristems are located at the tips of roots and shoots, while lateral meristems contribute to the increase in plant diameter.
• 🌱 Intercalary meristems are found at the nodes of plants, enabling the growth of new branches and leaves.
• 🌲 Lateral meristems in woody plants form annual rings, which can be used to determine the age of the plant.
• 🌳 The strategic placement of meristematic tissues allows plants to grow continuously throughout their life.

Q & A

What is the definition of tissues in the context of the plant kingdom?

Tissues in the plant kingdom are groups of cells that share similar structure and work together to carry out a specific function.

How do plant tissues differ from animal tissues?

Plant tissues are comparatively simple and are tailored to meet the stationary lifestyle of plants, which involves growing tall, preparing their own food, and absorbing water from the soil.

What are the two fundamental types of tissues found in plants?

Plant tissues can be fundamentally divided into dividing tissues, also known as meristematic tissues, and non-dividing tissues, also known as permanent tissues.

Why are non-dividing or permanent tissues more abundant in plants than dividing tissues?

Non-dividing or permanent tissues are more abundant because they are formed from the meristematic tissue itself. Each time a meristematic cell divides, one cell remains meristematic and the other becomes part of the permanent tissue.

What is the term used to describe the process of specialized tissues forming from meristematic tissue?

The process of specialized tissues forming from meristematic tissue is called differentiation.

What are the special characteristics of cells that make up meristematic tissue?

Cells of meristematic tissue have very thin cell walls, dense cytoplasm, prominent nuclei, and they typically do not have vacuoles due to their rapid division.

Where are meristematic tissues found in a plant?

Meristematic tissues are found in growing regions of the plant such as the shoot tip, root tips, lateral parts for increasing diameter, and nodal areas where new branches and leaves grow.

What are the different types of meristematic tissues based on their location in the plant body?

Based on their location, meristematic tissues are categorized as apical meristem (at the apex of roots and shoots), lateral meristem (in the lateral parts), and inter-calorie meristem (in the nodal areas).

How can the age of a plant be determined from its structure?

The age of a plant can be determined by counting the annual rings formed by the division of lateral meristem, which are visible in the cross-section of a woody plant's trunk.

What happens to a plant when the tip of the shoot is cut off?

When the tip of the shoot is cut off, a new shoot arises from the inter-calorie meristematic area at the nodes, allowing the plant to continue growing.

Why doesn't the grass blade regain its pointed tip after being grazed upon?

The grass blade doesn't regain its pointed tip after being grazed because cell division and development occur in the inter-calorie meristematic area, not at the tip.