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Leaf Chemical

October 24, 2005

The trees are starting to put on their spectacular autumn show. Why and how do they do it?


Secrets of autumn leaves. I’m Bob Hirshon and this is Science Update.

This time of year, the green pigment chlorophyll disappears from leaves, unmasking the brilliant colors of autumn. It’s all part of a larger mission to salvage the nutrients in the leaf and store them for the winter.

Stefan Jansson and his colleagues at the Umea Plant Sciences Institute in Sweden recently identified a key player in this process. It’s a chemical that breaks down the protein that clumps chlorophyll molecules together. He says it’s not clear yet what activates the chemical in the fall.

STEFAN JANSSON (Umea Plant Sciences Institute, Sweden):
We can watch sort of the workers but we can’t observe the guy that actually decides. That’s what we hope in the future to find out, but we’re not there yet.

He says understanding how trees prepare for winter could help scientists breed hardier trees. I’m Bob Hirshon, for AAAS, the science society.