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.

Outlines

00:00

🌿 Meristematic and Permanent Tissues in Plant Growth

This paragraph delves into the concept of plant tissues, focusing on meristematic and permanent tissues. Meristematic tissues, characterized by rapidly dividing cells, are crucial for plant growth, occurring at the tips of stems and roots. As these cells age, they differentiate into permanent tissues, which can be simple or complex. Simple permanent tissues include parenchyma, which is involved in photosynthesis and food storage, and collenchyma, providing mechanical support and flexibility. Complex permanent tissues consist of xylem and phloem, responsible for the transport of water, minerals, and sugars throughout the plant. The paragraph also touches on the transformation of meristematic tissues into permanent ones, emphasizing the process of differentiation.

05:00

🛡️ Complex Permanent Tissues and Protective Layers in Plants

The second paragraph explores complex permanent tissues, specifically xylem and phloem, and their components. Xylem is composed of tracheids, vessels, xylem parenchyma, and xylem fibers, which together facilitate water and mineral transport and provide structural support. Phloem includes sieve tubes, companion cells, phloem parenchyma, and phloem fibers, responsible for the distribution of sugars and food storage. Additionally, the paragraph discusses protective tissues such as the epidermis, which serves as the outer layer of fruits, stems, and leaves, and cork, a secondary protective layer in older roots and stems. The epidermis is highlighted for its role in gaseous exchange through stomata and its waterproof cuticle, while cork cells are noted for their impermeability due to suberin deposition.

10:03

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Keywords

💡Tissue

Tissue refers to a group of cells that are similar in structure and function together to perform a specific role within an organism. In the context of the video, plant tissues are highlighted as crucial for growth and structural support. The video mentions meristematic and permanent tissues, which are essential for plant development and maintenance.

💡Meristematic Tissue

Meristematic tissue is a type of plant tissue composed of rapidly dividing cells that contribute to the growth of the plant. The video explains that these tissues are responsible for the increase in length at the tips of stems and roots. Meristematic tissues are classified into apical, lateral, and intercalary, each playing a distinct role in plant growth.

💡Apical Meristem

Apical meristem is a specific type of meristematic tissue located at the growing tips of stems and roots. It is responsible for increasing the length of the plant. The video uses the example of a plant growing month by month, attributing this growth to the activity of apical meristems.

💡Differentiation

Differentiation in plants is the process by which cells take on a permanent shape, size, and function. The video describes how old meristematic cells lose their ability to divide and transform into permanent tissues, a process indicative of the maturation of plant cells.

💡Permanent Tissue

Permanent tissues are those that have undergone differentiation and no longer divide. They have specific roles in the plant, such as structural support or nutrient conduction. The video contrasts meristematic tissues with permanent tissues, highlighting their different functions in plant anatomy.

💡Parenchyma

Parenchyma is a type of simple permanent tissue composed of living cells that perform various functions like photosynthesis, storage, and providing structural support. The video describes parenchyma cells as being found in the central cortex of stems and roots and in leaves, where they contain chloroplasts and are known as chlorenchyma.

💡Collenchyma

Collenchyma is a simple permanent tissue made up of living cells with irregularly thickened cell walls, providing mechanical support and flexibility to plant structures. The video mentions that collenchyma cells are found in the peripheral regions of stems and leaf stalks, contributing to the plant's structural integrity.

💡Sclerenchyma

Sclerenchyma is a simple permanent tissue consisting of dead cells with lignin in their cell walls, offering strength to the plant. The video explains that sclerenchyma is found in vascular tissues, veins of leaves, and the covering of seeds and nuts, playing a critical role in the structural support of plants.

💡Complex Permanent Tissue

Complex permanent tissues are composed of more than one type of cell that work together to perform a common function. The video identifies xylem and phloem as examples of complex permanent tissues, both of which are essential for the transport of water, nutrients, and sugars within the plant.

💡Xylem

Xylem is a complex permanent tissue responsible for the transport of water and minerals from the roots to the rest of the plant. The video describes the components of xylem, including tracheids, vessels, xylem parenchyma, and xylem fibers, each contributing to the structural and functional aspects of water transport.

💡Phloem

Phloem is another complex permanent tissue that transports sugars and food from the leaves to other parts of the plant. The video details the elements of phloem, such as sieve tubes, companion cells, phloem parenchyma, and phloem fibers, which work together to facilitate the movement of nutrients.

💡Protective Tissue

Protective tissues, such as the epidermis and cork, shield plants from external factors and maintain their internal environment. The video explains that the epidermis is the outermost layer of fruits, stems, and leaves, featuring stomata for gas exchange and a waterproof cuticle. As the plant matures, secondary protective tissues like cork develop, providing additional defense.

Highlights

Plant tissues are categorized into meristematic and permanent tissues, with unique functions for growth and structure.

Meristematic tissues are responsible for plant growth, found at the tips of stems and roots, and are rapidly dividing.

Different types of meristematic tissues include apical, lateral, and intercalary, each contributing to various aspects of plant growth.

Meristematic cells are characterized by being living, cubicle, and thin-walled with large nuclei and no intercellular spaces.

Old meristematic cells lose their ability to divide and transform into permanent tissues through a process called differentiation.

Permanent tissues can be simple or complex, with simple tissues including parenchyma, collenchyma, and sclerenchyma.

Parenchyma tissue is the ground tissue in stems, roots, and leaves, playing a role in photosynthesis and food storage.

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

Sclerenchyma tissue consists of dead cells with lignin in their cell walls, offering strength to plant structures.

Complex permanent tissues, such as xylem and phloem, are made up of multiple cell types working together for common functions.

Xylem includes tracheids and vessels for water transport, xylem parenchyma for storage, and xylem fibers for support.

Phloem consists of sieve tubes for transporting sugars, companion cells, phloem parenchyma, and phloem fibers for support.

Protective tissues like epidermis and cork shield plants from the environment, with stomata aiding in gaseous exchange.

Epidermal cells of roots have hair-like structures for absorption, while secondary meristems form a protective layer in older plants.

Cork cells in older roots and stems are impermeable to gases and water due to thickened cell walls with suberin.

Plant growth is a dynamic process involving the transformation of meristematic tissues into permanent tissues for structural support and function.

The various types of plant tissues highlight the complexity and specialization required for plant survival and adaptation.

Transcripts

a group of cells that are similar in

structure and that work together to

achieve a particular function forms like

tissue

plants are stationary and so some of the

tissues they have are dead cells which

provide mechanical strength these are

the different types of plant tissues

meristematic and permanent tissues

look at how this plant is growing month

by month

this is due to a special type of tissue

called meristematic tissue

these tissues are rapidly dividing

tissues

plant growth occurs only at those points

where these tissues are present the tips

of the stem and the root

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meristematic cells are living cubicle

and thin-walled each cell has a large

nucleus cells are closely packed with no

intercellular spaces

depending on the region where they are

present meristematic tissues are

classified as apical lateral and inter

calorie

apical meristem is present at the apical

or growing tips of stems and roots it

increases the length of the plant

lateral meristem or cambium is present

in the radial portion of the stem or

root it increases the girth of the plant

intercalary meristem occurs at the base

of the leaves or at the inter nodes it

helps to increase the length of the

inter node

what eventually happens to these

metastatic tissues

old meristematic cells lose the capacity

to divide and transform into permanent

tissues this process of taking up a

permanent shape size and function is

called differentiation

permanent issues can be simple or

complex depending upon their structure

and function

look at the stem of the plant

what tissue is the stem meters

stem is made of the tissue baton climber

badan khaimah consists of elongated

living cells with a thin cell wall made

of cellulose

these cells are polygonal in shape and

have a large central vacuum

they also have intercellular spaces

between them they are found loosely

packed with unspecialized cells

parenchyma forms the ground tissue in

the central cortex and the peripheral

bit of stems and roots

in leaves they contain chloroplasts and

are called chlorin Kaymer which help in

photosynthesis

in aquatic plants parenchyma tis cells

contain large air cavities that help in

buoyancy and are called Erin Kaymer

parenchyma tease cells in fruits and

vegetables are filled with starch which

help in food storage

let's take a look at another simple

permanent tissue the colon Kaymer colon

Kaymer consists of elongated living

cells with cell walls made of cellulose

and pectin these cells have irregularly

thickened at the corners and have little

intercellular spaces

they occur in the peripheral regions of

stems below the epidermis in leaf stalks

leaf mid ribs and also in herbaceous

dicot stems

: Kaymer tissues provide mechanical

support and flexibility in plants here

is another type of simple permanent

tissue that sclerenchyma

these are long narrow cells with no

intercellular spaces sclerenchyma

consists of dead cells with lignin

deposited in their cell wall they occur

in the vascular tissues of stems veins

of leaves and in the covering of seeds

and nuts these tissues provide strength

to the plant

what are complex permanent issues

complex permanent tissues are made of

more than one type of cells that

coordinate together to perform a common

function

these are of two types namely xylem and

phloem

let's explore the different components

of the xylem track yet

vessels

xylem parenchyma

and Siloam fibers

tracheids are tubular dead cells they

transport water their cell wall is made

of lignin which provides mechanical

support

vessels

our elongated dead cells with bits that

transport water and minerals they are

usually present in big trees

xylem parenchyma cells are living and

they store thought

xylem fibers

are elongated dead cells with lignin

that provide mechanical support

let's now look at the different elements

of phloem

see tubes

companion cells

slowin parenchyma and slowing fibers

save tubes are elongated living cells

with perforated walls they transport

sugar or food from the leaves to the

stem and the roots

companion cells are small elongated and

help in conduction of food

slow and parenchyma store and transport

food

phloem fibers

I'll pick Walt elongated dead cells

which provide mechanical support

another type of tissue that is very

important for plants is the protective

tissue they protect plants from the

surroundings protective tissues include

epidermis and cop

epidermis is the outermost protective

layer of fruits stems

and leaves it is one cell thick and

covered with a waterproof layer called

cuticle these cells are continuous flat

and have no intercellular spaces

the epidermis is perforated by the

presence of stomata at certain places

stomata are surrounded by guard cells

and help in gaseous exchange and loss of

water epidermal cells of the root bear

hair like things that help in absorption

as the plant grows older secondary

meristems replace the outer protective

tissue this Altemus layer in older roots

and stems is called kaak kaak cells are

dead and lack intercellular spaces cell

walls are thickened by suberin which

makes them impermeable to gases and

water

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