CBSE Class 6 Science Revision Notes Chapter 7

CBSE Class 6 Science Revision Notes Chapter 7 – Getting to Know Plants

Class 6 Science Chapter 7 Notes on Getting to Know Plants is a complete guide for students to know about different types and classifications of plants. These Revision Notes are prepared by subject matter experts from the most recent CBSE (NCERT) books. Class 6 Science Chapter 7 Notes on Extramarks helps students improve their exam results. Students can access these CBSE (NCERT) notes easily from Extramarks’ website. 

Revision Notes for CBSE Class 6 Science Chapter 7 

Access Class 6 Science Chapter 7 – Getting to Know Plants Notes

Introduction

There are numerous types of plants in the environment. Some of them have different types and colours of leaves, flowers, and fruits, thick or thin stems, and are small or tall. All plants have roots, stems, leaves, and buds regardless of their colour, size, or shape.

Classification of Plants

Similar types of plants can be grouped together based on these traits since different plants have different sizes or types of stems. They fall into the following categories:

1) Based on the Size of the Plant and the Type of Stem

The stems of the plants can be hard, tender, or soft, and they come in a variety of sizes. The various kinds are as follows.

Herbs

Herbs are plants with green, tender stems that are typically small in size.

The majority of these plants are  herbs used in cooking and medicine.

For example, tulsi, mint, mustard, wheat, etc.

Shrubs

Shrubs have small branches that extend from the plant’s base and are attached to a hard stem on these plants.

They are larger than herbs but smaller than trees.

Roses, sunflowers, tea, etc., are examples.

Trees

Trees are the largest plants, with thick, woody stems, and numerous branches.

Wood is frequently used to construct homes and furniture.

Mango, neem, teak, etc., are examples.

Creepers

Creepers, as the name suggests, are plants that creep on the ground. They have very fragile, long, thin stems that can neither stand erect nor support all their weight.

Pumpkin, cucumber, etc., are examples.

Climbers

Climbers are weak-stemmed plants that seek support for their growth by clinging to objects like trees.

For example, pea plants, money plants, etc.

2) Based on the Life Cycle of Plants

Plants can be classified based on how long it takes them to complete their entire life cycle.

1. Annuals: These are plants whose life cycles are completed in a single season. For example, wheat, rice, corn, etc.
2. Biennials: The life cycle of these plants is completed over the course of two seasons. For example, bananas, carrots, onions, etc.
3. Perennials: These plants typically have long lifespans and require more than two years to complete their life cycle. For example, mango and apple plants.

3) Based on Flowers

The flowers on the plants could be present or absent. As a result, they can be broadly divided into the following.

1. Flowering Plants

These are the plants that bear flowers.

Rose, jasmine, papaya, etc., are some examples.

1. Non-Flowering Plants

These plants do not bear flowers.

Ferns and moss are examples.

Parts of a Plant

A plant primarily consists of two parts: the shoot system, which is located above the ground or soil, and the root system, which is located below.

Most of a plant’s parts are edible. Some examples include:

• Leaves – Spinach, cabbage, and onion
• Stems – Celery
• Flowers – Broccoli and cauliflower 
• Fruits – Banana and mango
• Seeds – Pulses
• Roots – Carrot and radish

Shoot System

The shoot system includes all parts that are above the soil, such as the stem, leaves, buds, flowers, and fruits.

1) Stem

• The stem is the primary component of the plant, from which all other parts are borne. It carries fruits, flowers, buds, leaves, and branches.
• It gives the plant support and maintains its upright posture.
• The primary purpose of the stems is to transfer water and minerals from the soil to various plant parts.
• To see this, a simple experiment can be conducted. When a freshly cut plant stem is placed in a reddish water solution, the red colour is present in both the freshly cut stem and the leaves after some time.
• Sometimes the stem is also modified to store food as in potato (underground) or to threadlike structures called tendrils for climbing.

2) Leaf

The leaf is a part of the plant that is joined to the stem and is typically green in colour. It could also come in other colours, like in the case of some ornamental plants.

The petiole of the leaf refers to the point where it attaches to the stem.

The lamina is the broad, flat portion of the leaf.

The leaf has a few lines that are known as veins. The midrib is a central main line that can be seen in the leaf.

Leaf venation refers to the pattern the leaf’s veins create. There are two varieties of this venation:

1. Reticulate venation: The veins on either side of the midrib form a pattern resembling a net. Mango leaf is an example.
2. Parallel venation: In this type of venation, the design of the veins is parallel to each other. Grass is an example.

The leaf serves two main purposes:

Transpiration

“Transpiration is the biological process by which water is lost in the form of water vapour from the aerial parts of the plants.”

This ensures that the plant’s water balance is preserved for its survival.

To observe this, a polythene cover is tied around a plant’s leaf. After some time, water droplets start to appear inside of it, indicating transpiration via the leaf.

Photosynthesis

When sunlight, carbon dioxide, and water are present, chlorophyll, a green pigment in the leaves, prepares food for the plant. During this process, oxygen is also released into the air.

3) Bud

It appears as a brief stem projection.

4) Flowers

The colourful, visually appealing part of the plant is its flower. Flowers might also have a scent. By looking at the colour and shape of the flowers, such as those on roses and marigolds, it is simple to recognise the plants.

The following are a flower’s main components.

• Sepal
• A flower’s outermost layer of tiny structures resembling leaves is called a sepal.
• They serve to safeguard the flower and support the petals.
• They are primarily green in colour.
• Petals
• Following the sepals, the petals are the coloured layer. 
• They might come in a variety of hues and forms. Sunflowers and roses both have unique shapes and hues.
• Petals are vividly coloured to attract pollinating insects and birds. 
• They also shield the flower’s inner layers.
• Stamen
• These are the flower’s male reproductive organs. 
• A stamen has a swollen end and is long, thread-like in shape. 
• These come in various numbers and sizes.
• A filament is a long, thin tube that is used to make each stamen.
• The anther is the swollen section of the filament that transports the pollen grains.
• Pistil
• It is the flower’s female organ. 
• The pistil typically resides in the flower’s centre. 
• It is made up of three components: the stigma, the style, and the ovary. The pedicel secures it to the plant.
• The stigma is the gooey portion at the top of the pistil that receives the pollen grains.
• It is attached to the style, a long, thin tube that transports pollen grains to the ovary.
• The ovules, or budding seeds, are located in the ovary, a swollen region at the tip of the pistil.

Root System

It consists of the roots, or parts of the plant that are underground.

As they draw water and minerals from the soil, the roots are crucial for plants. This is then moved by the stem to the various parts of the plant where food preparation takes place, aiding in the plant’s growth.

The roots also function as an anchor for the plant as it holds the plant firmly to the ground and lets it stand straight. 

The food that is stored in the roots is also edible.

There are two types of roots:

1. Tap Root

A tap root is characterised by one primary root that extends deep into the soil. It has numerous tiny roots that sprout from it.

This root holds firmly in the ground and penetrates deeply into the soil, making it firmer and more difficult to pull out.

They frequently contain food storage, which makes them useful to people. They may take on various forms.

Examples include turnips, carrots, and mango.

1. Fibrous Roots

This type of root does not have a main root and it has many roots that are almost of the same size.

These roots do not penetrate the soil deeply because they spread out like a thread-like structure, and are easy to remove.

Examples include grass and onions.