|MadSci Network: Botany|
Purple, red or blue-leaved plants, such as purple cabbage, red Japanese maple and blue Colorado spruce, usually contain large amounts of anthocyanin pigments that mask the green chlorophyll. A common student lab exercise involves extracting water soluble anthocyanins from purple cabbage to make a pH indicator. Yellow-leaved plants usually contain large amounts of carotenoid pigments that mask the green chlorophyll. Green leaves usually contain large amounts of yellow carotenoid pigments that are masked by the green chlorophyll. In the fall, many leaves turn yellow because the green chlorophyll degrades to reveal the yellow carotenoids that were there all season. A widespread misconception in biology teaching is that green plant leaves reflect all the green light they receive. However, green leaves often absorb about half the green light they receive and use it in photosynthesis. Green leaves are green because they reflect more green light than other colors. References Hershey, D.R. 2004. Avoid misconceptions when teaching about plants Re: How much light does chlorophyl absorb? How much other materials?
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