• Question: why do leaves change during the fall?

    Asked by whdavandbeat to Anil, Blanka, Cees, Emma, Mike on 3 Jul 2012.
    • Photo: Emma Trantham

      Emma Trantham answered on 3 Jul 2012:

      Leaves are green because they contain a green pigment called chlorophyll. This green pigment hides all of the other colours. The chlorophyll helps the plant to absorb sunlight and use the sunlight to make food. The chlorophyll is constantly being broken down and new chlorophyll is made.

      In autumn/the fall there is less sunlight so actually havign to make chlorophyll would use mroe energy than it would create. The plant cuts off the veins supplying its leaves so the leaves run out of water and nutrients and so they don’t make any more chlorophyll.

      Now there is no green pigment you can see the other pigments that colour the leaf (which is why the leaf looks reddy/brown).

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