Have you ever noticed that plants do not go to the market to buy food? That is because plants are amazing -- they make their own food! They use sunlight, water, and air to prepare food right inside their leaves.
Plants also have beautiful flowers that do a very important job -- they help the plant make seeds so that new plants can grow. In India, we see flowers everywhere -- marigolds at festivals, lotus in ponds, and jasmine in gardens. Let us discover the wonderful world of plants!
The process by which plants make their own food is called photosynthesis. The word "photo" means light and "synthesis" means to make. So photosynthesis means "making food using light."
What plants need for photosynthesis:
What plants produce:
So plants take in carbon dioxide and give out oxygen. This is why trees are so important -- they clean the air for us.
Think about it: Why do plants kept in a dark room turn yellow and weak? Without sunlight, they cannot make food!
A flower has four main parts. Each part has a special job:
| Part | Description | Function |
|---|---|---|
| Sepals | Small green leaf-like parts at the base of the flower | Protect the flower bud before it opens |
| Petals | The colourful parts of the flower | Attract insects and birds for pollination |
| Stamen | The male part; has a thin stalk (filament) with a tip (anther) that holds pollen | Produces pollen grains (the yellow powder) |
| Pistil | The female part; found in the centre with a sticky top (stigma), a tube (style), and a base (ovary) | Contains ovules that become seeds after pollination |
The hibiscus (gudhal) flower is a good example to study because all four parts are large and easy to see.
Pollination is the transfer of pollen from the stamen (male part) to the pistil (female part) of a flower. After pollination, seeds begin to form.
Pollination by insects: Bees, butterflies, and other insects visit flowers to drink nectar (a sweet liquid). While doing so, pollen sticks to their body. When they visit another flower, the pollen rubs off onto the pistil. Bright petals and sweet smell attract insects. Marigold and sunflower are pollinated by insects.
Pollination by wind: Some flowers do not have bright petals or sweet smell. Their pollen is light and carried by the wind to other flowers. Grass, wheat, and rice are pollinated by wind.
Think about it: Why do you see bees buzzing around flowers in a garden? They are helping the flowers with pollination!
| Word | Meaning |
|---|---|
| Photosynthesis | The process by which plants make food using sunlight, water, and carbon dioxide |
| Chlorophyll | The green substance in leaves that traps sunlight |
| Stomata | Tiny holes on leaves through which gases enter and leave |
| Pollination | Transfer of pollen from stamen to pistil |
| Seed dispersal | The spreading of seeds away from the parent plant |
| Germination | The process by which a seed begins to grow into a new plant |
After pollination, seeds form inside the fruit. If all seeds fell right under the parent plant, they would be too crowded and would not get enough sunlight or water. So nature has clever ways to spread seeds far away. This is called seed dispersal.
| Method | How It Works | Indian Examples |
|---|---|---|
| By wind | Seeds are light, have wings or hair-like structures that help them float in the air | Dandelion, maple, drumstick (sahjan), cotton |
| By water | Seeds float on water and travel to new places | Coconut (travels across rivers and seas), lotus |
| By animals | Animals eat fruits and drop seeds elsewhere; some seeds stick to animal fur | Mango, guava, berries (eaten by birds); gokhru seeds stick to clothes |
| By bursting | Some fruits burst open when ripe and scatter seeds around | Balsam (gul mehndi), pea pods, lady's finger (bhindi) |
Think about it: Have you seen tiny seeds stuck to your socks after walking through a field? Those seeds are using you for dispersal!
Germination is the process by which a seed grows into a new baby plant (seedling). For germination, a seed needs:
Steps of germination: The seed absorbs water and swells. The seed coat breaks open. A tiny root grows downward into the soil. A tiny shoot grows upward toward the sunlight. Leaves appear, and the plant begins to make its own food through photosynthesis.
You can see germination at home by placing moong (green gram) seeds on a wet cotton pad. In 2-3 days, you will see tiny white roots and green shoots.
Many Indian homes have a tulsi (holy basil) plant in the courtyard. The tulsi plant uses sunlight, water from the soil, and carbon dioxide from the air to make its food. It gives out oxygen, which makes the air around the house fresh and clean.
In Punjab and Haryana, large mustard (sarson) fields bloom with bright yellow flowers in winter. Thousands of bees visit these flowers to collect nectar. While doing so, they carry pollen from one flower to another, helping the mustard plants produce seeds.
In Kerala, coconut palms grow along the coast. When a ripe coconut falls into the sea, it can float for weeks and travel to a distant shore. There, it germinates and grows into a new coconut tree. This is seed dispersal by water.
A. Fill in the Blanks
B. Multiple Choice Questions
C. Short Answer Questions
Grow Your Own Plant: Take 5 moong (green gram) seeds. Place them on a wet cotton pad in a small bowl. Keep the cotton moist and place the bowl near a window. Observe the seeds every day for one week and fill in the table below.
| Day | What I See (Draw or Write) | Did the Seed Change? (Yes / No) |
|---|---|---|
| Day 1 | ||
| Day 2 | ||
| Day 3 | ||
| Day 5 | ||
| Day 7 |
On which day did you first see a root? Day __________ A shoot? Day __________