Plant Coloration and Energy
Location: Outside U.S.
Date: Spring 2012
Does it require more energy for a plant to produce pigmented flower petals than white petals? I'm interested in learning whether it "costs" plants more, energy-wise, to produce color. I take my students out on a weekly nature walk, and the spring wildflowers are just coming into bloom in the forest. Most of these are white and low-growing. As the only flowers in bloom, most of these flowers are white - they stand out against the evergreen foliage and the duff of last year's leaves, thus color isn't required to attract pollinators. They do invest energy to produce scent - which makes sense as many of these are often somewhat covered by leaf-litter, but color is mostly restricted to white.
Plants need to invest energy to produce pigmented flower petals. Typical colors are produced from the amino acid phenylalanine but in making the pigments the nitrogen is removed leaving a carbon, hydrogen, oxygen-containing molecule. White is the absence of pigmentation. Investment in scent probably has a better payoff than to invest in color.
Take care, Jim
Jim Tokuhisa, Ph.D.
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Update: June 2012