Why do leaves change colour in autumn? || Plant pigments explained || #sabasohail || #scipeak

Why do leaves change colour in autumn? 🍁🌳
Have you ever walked through a park in autumn and wondered why the green leaves turn brilliant shades of yellow, orange, and red before falling? Here’s the beautiful science behind it.
✅ Why are leaves green in the first place?
Leaves are green because of chlorophyll, the pigment that absorbs sunlight to carry out photosynthesis, allowing plants to make their food by converting sunlight, water, and carbon dioxide into glucose and oxygen.
✅ What happens in autumn?
As days become shorter and temperatures drop, plants prepare for winter. Trees begin to shut down their food-making process to conserve energy. The chlorophyll in leaves breaks down and is reabsorbed by the tree to store nutrients for the next growing season.
✅ Why do different colours appear?
When green chlorophyll fades away, other pigments present in the leaf become visible:
🍂 Carotenoids:
• These pigments produce yellow and orange colours.
• They are always present in the leaf but are masked by the dominant green chlorophyll during the growing season.
🍁 Anthocyanins:
• These pigments produce red, purple, or crimson colours.
• Unlike carotenoids, anthocyanins are produced in autumn. Their formation is triggered by bright light and excess plant sugars trapped in the leaves.
✅ Why do trees do this?
The colour change is a sign that the tree is entering dormancy to survive winter. As chlorophyll breaks down, trees reabsorb valuable nutrients like nitrogen and phosphorus from the leaves before they fall off. This recycling process helps the tree conserve resources for spring growth.
✅ Do weather conditions affect autumn colours?
Yes! The most vibrant colours appear when:
• Sunny days and cool nights occur in early autumn.
• Sunlight increases anthocyanin production (red pigments), while cool nights slow the movement of sugars out of the leaves, enhancing reds and purples.
✅ Is this only in certain trees?
Mostly deciduous trees – those that shed their leaves annually – show dramatic colour changes. Coniferous trees like pines remain green all year.
So, next time you see a tree ablaze with autumn colours, remember it’s not just for beauty – it’s a sign of the tree’s preparation for winter, recycling nutrients, and protecting itself through dormancy. Nature combines chemistry, biology, and seasonal cycles to create the breathtaking scenery we enjoy every year.
✨ Video by Scipeak | Written and narrated by Saba Sohail.
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Видео Why do leaves change colour in autumn? || Plant pigments explained || #sabasohail || #scipeak канала SciPeak