![]() In this case too, the protective logic of red pigmentation may be sound, but why are there more yellow-leaved trees in fall in Europe, if red leaves are an advantage?Īccording to the theory provided by Prof. Trees that expend the energy to color their leaves red may benefit from fewer aphids and fewer aphid eggs. ![]() Aphids are attracted to yellow leaves more than red ones. Insects tend to suck the amino acids from the leaves in the fall season, and later lay their eggs, to the detriment of the trees. But whatever the answer is, these explanations do not help us understand why the process of creating anthocyanin, the red pigment, does not occur in Europe.Īn evolutionary ecology approach infers that the strong autumn colors result from the long evolutionary war between the trees and the insects that use them as hosts. Other explanations suggest that the red pigment is produced as part of the tree's strategy for protecting itself against insects that thrive on the flow of amino acids. Some research suggests that the red pigment is produced as a result of physiological functions that make the re-translocation of amino acids to the woody parts of the tree more efficient in setting up its protection against the potential damage of light and cold. These facts were only recently discovered and led to a surge of research studies attempting to explain why trees expend resources on creating red pigments just as they are about to shed their leaves.Įxplanations that have been offered vary and there is no agreement on this as of yet. Red autumn leaves result from a different process: As the chlorophyll diminishes, a red pigment, anthocyanin, which was not previously present, is produced in the leaf. When the green chlorophyll in leaves diminishes, the yellow pigments that already exist become dominant and give their color to the leaves. The change in color to red or yellow as autumn approaches is not the result of the leaves' dying, but is rather the result of a series of processes – which differ between the red and yellow autumn leaves. The green color of a tree's leaves is mainly due to chlorophyll pigment. Jarmo Holopainen of the University of Kuopio in Finland and published in the Journal New Phytologist proposes taking a step 35 million years back to solve the color mystery. Simcha Lev-Yadun of the Department of Science Education- Biology at the University of Haifa-Oranim and Prof.
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