Where to find all you need to know about the natural world
Grow your knowledge of flower-related facts with Flora: Inside The Secret World of Plants
Why do leaves on the trees turn yellow and orange, or red, or purple, at the same time each year – virtually every leaf, on every branch, of every deciduous tree, every autumn? Have you ever wondered? Ever really wondered?
Flora: Inside The Secret World of Plants has the answers. Within this beautifully illustrated tome, discover all sorts of fascinating facts about plants: from their roots to their stems, their flowers to their fruits, and yes, even their leaves. What better gift to give a garden-lover this Christmas than an encyclopedic knowledge on all things flora?
Created in association with the world-famous Royal Botanic Gardens, Kew, this is a fascinating celebration of the natural world. It’s a love letter to the plant kingdom, detailing all aspects from roots to stems, from branches to leaves, and from flowers to seeds and fruits.
So, what about those leaves? As Flora: Inside The Secret World of Plants explains:
Leaves are usually green owing to a chemical compound called chlorophyll. Chlorophyll absorbs sunlight and, in a process called photosynthesis, uses carbon dioxide and water to convert it into glucose, which the plant uses as food. Chlorophyll absorbs parts of sunlight that are red and blue-violet but reflects the parts that are green. This is why throughout the months of spring and summer, the leaves of many deciduous trees appear green.
All this changes, however, when the nights draw in and the temperature cools – signs which alert trees and shrubs that winter is coming. During this time, plants start to produce hormones which tell their leaf tissues their work is done and the time has come for them to fall.
As a result of this, chemical changes occur inside the leaves which make them change colour. Because in addition to the green pigment chlorophyll, there are other chemical compounds present all year round in leaves called carotenoids.
When chlorophyll inside the leaves starts to degrade, the yellow and orange carotenoids become more visible. (Why are they yellow and orange? They absorb green and blue light, but reflect yellow and red, hence their yellowy orange appearance.)
But what about red leaves? And purple leaves?
Leaves turn red-purple when starches inside them start to break down into sugars. These react with other chemicals to create “anthocyanins”, another pigment which is red-purple in hue. Leaves appear red if the tree’s sap is acidic, and purple if it’s alkaline.
This is why we get our gorgeous golden autumnal palette.
Is that thirst for knowledge fully satiated? Or do you want to know more? Like why some leaves sting – such as nettles? Or how other leaves enable carnivorous plants to ensnare prey – such as pitcher plants? Or about the very make-up of leaves, and what a plant actually is?
You need to get your hands on Flora: Inside The Secret World of Plants – the perfect gift for a gardening friend.
Flora: Inside The Secret World of Plants, £30
Available now at Amazon.co.uk
*This content was commissioned and approved by DK