Like animals, plants need food for energy to survive and grow, but while animals can move about to catch their food or find new areas of vegetation, plants are usually rooted to one spot. But plants can do something that no animal can do. They can make energy from sunlight. This process is called photosynthesis. As well as light, plants also need water and nutrients.
A plant may not look lively and active. But inside its millions of microscopic cells, thousands of chemical changes take place as part of the plant’s life processes. Like an animal’s body, a plant’s body has many specialized parts for different jobs. The roots take in water, minerals, salts and other substances from the soil in which the plant grows. The stiff stem holds the main parts of the plant above the surface, away from animals on the ground that might eat it, and above other plants so that the leaves can catch more sunlight.
A plant’s leaves are “light-powered food factories”. They are broad and flat so that as much light as possible falls on them. A green substance called chlorophyll in the leaves catches or absorbs the energy in light. It uses this energy to make a chemical reaction. Water, taken up from the soil, and carbon dioxide, taken in from the air, join together to form sugar, which contains lots of energy in chemical form. The plant then uses the sugar to power its life activities. The process is called photosynthesis —a word meaning “making with light”.
The carbon dioxide for photosynthesis comes from the air. It seeps into the leaf through tiny holes in its lower surface, known as stomata. In addition to sugar, photosynthesis also produces oxygen, which seeps out into the air. Living things including ourselves need oxygen to survive. Plants help to top up its level in the air.
Picture Credit : Google