Learn Class 4 Science - Plants

A typical plant consists of roots, stem, leaves and may bear flowers and fruits. Green leaves make food through the process of photosynthesis. Leaves also carry out transpiration. Roots absorb water and important minerals from the soil. It also gives anchor to the plant. Stem helps in carrying the water and minerals from the root to various parts of the plant and carry food from the leaves to other parts. It also stores excess food. It also gives support to the plant.

Plants play very important role on earth. They provide food and oxygen to all other living things. Plants are seen almost everywhere. They grow on land, on mountains, in deserts and under sea. We know plants grow mostly from seeds when they get enough water, sunlight and air.

Parts of Plants

The Root System

Root is the underground part of the plants body and grows towards the force of gravity. It fixes the plant within the soil and absorbs water and mineral nutrients from the soil. It stores excess food.

Tap Roots

It consists of one main long thick root growing downwards from which many thinner roots develop. Taproot goes deep into the soil for searching for water and minerals. Examples: sugar beet or carrot, bean, tea, peepal etc. have tap root.

Fibrous Roots

In case of fibrous root there is no main root. It consists of a dense equal size roots that arise from the stem. The roots grow downward and outward from the stem, branching repeatedly to form a mass of fine roots. Fibrous root does go very deep in the soil. Example: lilies, grasses, wheat, rice, palm etc. have fibrous root.

Function of Roots

1. Roots attach the plant body to the ground. It provides support to the plant and helps in holding the plant firmly in the ground.
2. Root hairs of the plant absorb water and mineral from the soil and pass it to the stem.
3. Some roots like carrot, radish etc. store food.
4. Root bind the soil which otherwise may be blown away by wind or washed away by water. Root prevents soil erosion.

The Shoot System

It is the aerial part of the plant body and enables a plant to grow taller to gain access to energy-giving light, and helps plant to prepare food. It is composed of erect stems on which are attached leaves, flowers, branches and buds. Leaves are attached to the stem at regions called nodes.

Stem

It supports the upper parts of plants. It carries the water and nutrients needed for plants to grow from roots to leaves and food produced by the leaves to other part of plants. Big trees like neem, mango, peepal etc. have strong, thick and woody stem. Such stem is called trunk. Some plant have thick but soft stem, example banana. Some plants have weak, soft and green stem as in case of climbers and creepers, example watermelon, money plant etc.

Functions of stem

1. Stem provide support to the plant above the ground. It bears branches, leaves, buds, flowers and fruits.
2. Stem transport water and minerals from root to other parts of the plants. It also transport food prepared by the leaves to different part of the plants.
3. Some underground stem stores food such as sugarcane, potato, ginger etc.

Leaves

Leaves are of different shapes and sizes. The outer surface of the leaf has a waxy coating which protects the leaf. The flat surface of the leaf is called leaf blade or lamina. It has veins running across within the leaf. Tiny opening on the surface of the leaves called stomata helps in the exchange of gases. Stomata can be seen only under microscope.

Functions of Leaves

1. These are the parts of the plant where food is made by the process of photosynthesis. That’s why leaves are called the food making factories of green plants. Chlorophyll (green pigment) present in the leaves uses the energy in sunlight to turn water (H2O) and carbon dioxide gas (CO2) into sugar and oxygen gas (O2).
2. Leaves gives out oxygen in the process of photosynthesis. All living beings need oxygen to live.
3. Some leaves store food in them such as mint, cabbage etc.

Flowers

Flowers are the most attractive part of a plant. Each flower types have a different physical structure, color and scent from those of other flower type plants. Buds of the plants grows into flower and flower finally becomes fruit enclosing the seed or seeds. Some fruits have one seed such as mango and cherry. Some fruits have many seeds such as papaya and watermelon.

Uses of flower

1. Many flowers such as rose and jasmine are used for making perfumes.
2. Some flowers edible such as cauliflower, broccoli and banana.
3. Some spices are obtained from flower such as saffron or kesar from crocus flower and cloves is dried flower.
4. Flowers are used for decoration on different occasions and for preparing bouquets, garlands and rangoli.

Learning Videos for 4th Grade Science - Plants