|MadSci Network: Botany|
You cannot readily extrapolate from sea anemones to plants because their pigments and use of light are different. Unlike sea anemones, plants are designed to absorb most visible light for photosynthesis. You have not provided solid evidence that red flowers are rare or absent especially at high altitudes, and the previous answer noted that at least some red flowers occurred at high altitudes. The alpine flower website cited in the references has a number of pink or reddish flowers. Flower coloration is to attract animals as pollinators. Red flowers seem especially attractive to birds, particularly hummingbirds, so the number of red flowered species may have some relationship to the number of bird pollinated species. Your idea that reflecting just most of the red wavelengths, but not green, yellow, blue, orange, etc. would protect the plant is not logical. White flowers actually would reflect the most colors of light but white flowers are common at all altitudes. Plants do have accessory pigments, such as cartenoids, that are thought to help protect chlorophyll in leaves. Anthocyanins, that provide flower colors, protect from UV-B radiation. Therefore, any heavily pigmented flower may provide greater protection from UV-B at high altitudes. Plants also contain flavones and flavonols that absorb UV radiation and are colorless to human vision. However, colored petals do not have light-sensitive chlorophyll to protect so anthocyanins main function is apparently for coloration to attract pollinators. References Meeuse, B. and Morris, S. 1984. The Sex Life of Flowers. New York: Facts On File. http://126.96.36.199/flowers/: Alpine Flowers (link defunct as of 8/22/2006). Alpin floral collection How Carotenoids Protect Chlorophyll http://www.sciencenet.org.uk/database/Biology/Original/b00079d.html Why are some leaves permanently red or yellow? (link defunct as of 8/22/2006)
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