Where do autumn colours come from?
A colour palette needs pigments, and there are three types that are involved in autumn colour. • Chlorophyll, which gives leaves their basic green colour. It is necessary for photosynthesis, the chemical reaction that enables plants to use sunlight to manufacture sugars for their food. Trees in the temperate zones store these sugars for their winter dormant period. • Carotenoids, which produce yellow, orange, and brown colours in such things as corn, carrots, and daffodils, as well as rutabagas, buttercups, and bananas. • Anthocyanins, which give colour to such familiar things as cranberries, red apples, concord grapes, blueberries, cherries, strawberries, and plums. They are water soluble and appear in the watery liquid of leaf cells. Both chlorophyll and carotenoids are present in the chloroplasts of leaf cells throughout the growing season. Most anthocyanins are produced in the autumn, in response to bright light and excess plant sugars within leaf cells. During the growing season,
