Why Leaves Change Color: Why are leaves green and why do they turn yellow, red or orange in autumn? Learn the simple science behind chlorophyll, photosynthesis, plant pigments and the change in color of leaves.
Why Leaves Change Color: When we go to our garden, pots, fields or forests, the first thing that catches our eye are the green leaves of the trees. Do you know why leaves are green? Why not red, blue or black? The answer to this is hidden in science. The green color of leaves is due to a special pigment called chlorophyll. This chlorophyll also helps plants in making food.
What is chlorophyll?
Chlorophyll is a natural green pigment, which is found in the leaves and green shoots of plants. Its main function is to capture sunlight so that plants can make their food by taking the light (Photosynthesis). If there is no chlorophyll, plants will not be able to make food and it will be difficult for them to survive.
Why do leaves appear green?
There are many colors in the white light of the Sun. When this light falls on the leaves, chlorophyll absorbs most of the colors such as red and blue. But chlorophyll reflects the green light back again. This reflected green light reaches our eyes, so we see the leaves as green. For example, a red T-shirt appears red to us because it reflects red light. Similarly, leaves reflect green light, so they appear green.
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Why is chlorophyll so important for plants?
Plants with the help of chlorophyll-
– Captures the sun’s energy. – Take carbon dioxide from the air. – Take water from the soil. – Prepare food with their help. – In this process oxygen is released into the atmosphere.
This process is called Photosynthesis.
Why do leaves change color in autumn?
The leaves of many trees turn yellow, orange or red in the winter or fall. This happens because at this time there is less sunlight and plants reduce the production of chlorophyll. As chlorophyll is reduced, other pigments already present in the leaves, such as carotenoids and anthocyanins, become visible. Due to this the color of the leaves changes.
Do all plants have green leaves?
No. The leaves of most plants are green, but the leaves of some plants also appear red, purple or light yellow. This is because along with chlorophyll, other pigments are present in large quantities in them. Yet they contain chlorophyll and can photosynthesize.
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Do plants remain green even in artificial light?
Yes. If plants receive plenty of artificial light, which contains the wavelengths necessary for photosynthesis, they can grow normally. This is the reason why special LED lights are used nowadays in greenhouses and indoor farming.
Content Source: NASA Earth Observatory, Encyclopaedia Britannica, National Geographic, Royal Horticultural Society (RHS), Khan Academy.