• Question: You know trees that have red leaves, not green. How do they photosynthesis? I thought it was the green chlorophyll (or something) that photosynthesized, not red chlorophyll?

    Asked by lisaloo to Claire, Kate, Matt, Rob, Sam on 24 Jun 2013.
    • Photo: Sam Geen

      Sam Geen answered on 24 Jun 2013:

      Trees with red leaves are preparing for winter, and have started letting their leaves drop off. The cholrophyll has stopped being replaced, so you can see the red/brown stuff in the cells (like the cell walls) instead.

    • Photo: Kate Husband

      Kate Husband answered on 25 Jun 2013:

      Interestingly the sun emits most of its light in the green, so plants have evolved to have green chlorophyll because it’s the most efficient colour to be.

    • Photo: Matthew Pankhurst

      Matthew Pankhurst answered on 26 Jun 2013:

      Yep -chlorophyll is the main photosynthesising chemical in plants. In red plants there is chlorophyll, but there is also red pigments, so you see red (I’m pretty sure the red pigment in these plants is not photosynthesizing). When the leaf gets old the green chlorophyll degrades and turns different colours. However! Life is odd and there are always exceptions – there are a few examples of marine plants that photosynthesise without green chlorophyll – instead they have a red chemical that does pretty much the same thing. They harness a very, very primitive type of bacteria, one is called Acaryochloris marina. It might provide clues with how early life adapted to the environment of the day – which tells us something about what that early environment was like!

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