|MadSci Network: Botany|
Leaves contains other pigments in addition to green chlorophyll that can affect the overall shade of green. Carotenoids are red or orange pigments. Anthocyanins vary widely in color depending on the cell pH (acidity) and can be yellow, red, purple or blue. A common exercise uses the anthocyanin in red cabbage as a pH indicator. Some leaves are not even green because the chlorophyll is masked by the other pigments, for example purpleleaf plum, blue Colorado spruce, and coleus. Other factors that could affect the shade of green are leaf hairs, leaf thickness, and the leaf chlorophyll concentration. There is also more than one type of chlorophyll which differ slightly in color. Reference Red Cabbage Carotenoids and Anthocyanins in Fall Leaf Colors
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