4th Class Science Plants Plants

Plants

Category : 4th Class

LEARNING OBJECTIVES

This lesson will help you to:—

  • Understand about different types of roots.
  • Know about the roots that we use in our daily life.
  • Observe flowering plants.
  • Learn about different types of flowers and their uses.
  • Uses of flowers.
  • Examine wild and domestic plants.

 

Real Life Examples

  • The branch of Biology which deals with study of plants is called Botany.
  • Chocolate is a food made from cocoa beans.
  • Bananas contain a natural chemical which can make a person happy.

 

QUICK CONCEPT REVIEW

Parts of plants and their functions

1. Shoots: The part of the plant which grows upwards, above the ground forms the shoot. The shoot grows from a seed or from the main stem of a plant.

2. Roots: The part which grows underground forms the root. Roots hold the plant firmly in the ground.

3. Stems: The main support of the plant, above the ground is called the stem. Along the stem there can be branches, leaves and buds. The water and salts absorbed by the roots travel up the stem and into the leaves. The food is carried by the stem to all parts of the plant. In some plants, such as sugarcane extra food is stored in the stem. Potato and ginger are underground stems. We eat these stems. Stems come in many varieties.

1. Some stems are thick, strong and woody and are covered in bark.

Example: Stem of the neem tree.

2. Some stems are thick but they are soft.

Example: Stem of banana plant.

3. Some stems are weak. They climb with the help of a support.

Example: Stem of grapevine.

4. Leaves: Plants make their food in the leaves. If you look carefully at a leaf you will see some veins on its flat part. The veins bring water and salts to the leaves from the roots.

5. Flowers: Flowers are of various colors and smell sweet. We use flowers to make garlands, to put into vases and for decoration during festivals. Flowers help plants to reproduce. In order for a flower to produce fruits and seeds, the pollen from one flower has to be carried to another flower. Pollen is a fine yellow dust. It is carried by the wind, water or by small insects such as bees.

6. Fruits and Seeds: Fruits are formed from flowers. Fruits contain seeds. First, a tiny bud appears on the stem of a plant. The bud grows into a flower. Later on, the flower grows into a fruit. When a fruit is broken open or dries up, its seeds may fall into the soil near the plant. Some seeds have wings and are carried by the wind to places far away from the plant. Some seeds get carried by the water animals to faraway places. Some seeds are collected by people and planted in the soil. Seeds usually have a hard covering. Inside each seed there is a baby plant. When a seed is put into soil and provided with enough water, sunlight and air, it can grow into a new plant. This new plant later on produces more seeds. This is known as a life cycle.

 

Amazing Facts

  • The largest single flower is the Rafflesia or “corpse flower” They are generally 3 feet in diameter with the record being 42 inches.
  • A method used to verify the age of a tree is to count the rings in the tree’s trunk.
  • Petals are usually colorful, and they attract insects and birds that help with pollination.

 

IN THIS CHAPTER WE WILL FOCUS ON ROOTS AND FLOWERS

 

ROOTS

The root performs many functions primary of which are:

  • Fixation: The root fixes the plant firmly in soil.
  • Absorption: The root hairs absorb water and raw food materials (mineral salts) from the soil.
  • Conduction: The root sends water and mineral salts into the stem and leaves.
  • Storage: A certain amount of food is stored in the root which is utilized as it grows. In many plants like radish, turnip, carrot and sweet potato the root is modified for storing food.
  • Preventing soil erosion: Roots help to bind the soil particles and prevent them from being blown away by wind or water.

There are two main types of roots.

1. Top root is long and sturdy: When a long main root grows from the end of the stem and many small side roots grow from the main root, it is called a tap root E.g. mango, bean, etc. Thinner roots grow out of the tap root.

These roots are further divided into primary root secondary root and tertiary root.

2. Fibrous roots are made up of large number of equal-sized roots. It is formed when a number of roots grow from the end of the stem.

Example: Roots of onion, grass and wheat plants.

 

Historical preview

  • Lilies are presumed to have originated from the Far East and are one of the oldest plants known.
  • The names given to flowers date back many years and are some of the first words of spoken language. Many of these names have been removed from the dictionary over times such as buttercup, dandelion, holly, lavender and violet.

 

EXAMPLES OF TAP ROOT WE EAT

     

 

The Amazing Banyan Roots! (Aerial roots)

The banyan accomplishes its major growth and animated forms through its amazing and unique root system. Like most trees, banyans also have roots that live underground. Yet unlike most trees banyans have roots that begin their life above ground. These roots grow downwards from branches towards the ground. These ore called aerial roots. Roots of Mangroves: Mangrove trees grow in marshy, areas that have clayey soil. This soil holds a lot of water and very little air. Thus these trees produce roots that grows above the water and help the plant in breathing, besides holding the plant in place.                     

 

 

Misconcept/Concept

Misconcept: The roots of plants absorb water from the soil and have no other important functions.

Concept: The roots also help some plants to climb, e.g. cucumber. Some roots are used to support the plants e.g. Banyan. Some roots store food and water, e.g. carrot.

 

FLOWERS

Flowers are found in wide varieties of colors like red, orange, yellow, white, violet etc. Rose, Jasmine, Marigold, Sunflower all are flowers. Flower is very important part of the plant. It changes into fruits that contain seed in it. When the seeds get proper condition of air, sunlight and moisture, germinates into a new plant.

THE PARTS OF A FLOWER

   

FLOWERS IN EVERYDAY LIFE: Some flowers grow on trees like Magnolia, Dogwood, Cherry blossoms. Some flowers grow on bushes like Rose, Fuchsia, Buddlia, and Camellia.

    

Some flowers grow on creepers like Bougainvillea.

Some flowers grow in water like Water lilies, Lotus, Pondweed etc.

Some flowers bloom only at night like Night Gladiolus, Moon flowers. Evening primrose.

Some flowers bloom only in day and close at night like Morning glory.

Some flowers grow only in summers like Sunflower, Balsam. Jasmine, Chinese honeysuckle (Madhumaiti).

Some flowers grow only in winters like Oahlia. Carnation, Marigold, Rose,

Some flowers grow in the wild like Floss flower, Wild primula.

Some flowers are domesticated like Rose, Tulips.

 

FLOWERS ARE USED IN MANY WAYS

  1. Flowers used as food- Some of the flowers are used as food like "Kachnar" flowers, "Banana" flowers, 'Sahjan' flowers, etc. The extract of some flower like rose are used to make drinks called sherbet.
  2. Flowers used as medicines- Some of the flowers are used as medicines like calendula, saffron.
  3. Flowers used as decoration and worship- Flowers are used as decorations in functions and festivals or as gifts as in bouquet, making garlands and for worshipping gods and goddesses.
  4. Other purposes- Flowers are also used as dye to colour clothes. They are also used in making perfumes and essence. For example flowers of Rose, Jasmine, and Lavender etc. are used in making perfumes, soaps lotion and incense sticks.

Floral Motifs: Motifs is a design or a pattern on a cloth, wood, metal, marble or pottery. Floral designs make beautiful motifs. You must have seen floral designs on bed covers, cushion covers, curtains, and clothes on tiles.

   

Buying Flowers: The person who sells flowers is called a florist. Most of the towns have a whole sale market of flowers called "Fool Mandi". The florists buys flowers from the mandi and sells them to us. We can buy a single flower, a bunch of flowers, a bouquet, a garland or can also buy loose petals for rangoli.

 

Whom do trees belong to:

Trees and plants belong to each one of us. They are an important part of our environment. They give us flowers, fruits, grains, vegetables and also purify our air. They provide shelter and shade to many birds and animals.

Trees are such an important resource for us hence we should not cut trees. The forest department officials are responsible to present the cutting of trees. The government has made strict rules against cutting of trees.

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