Not_Leopard_Seal

Not_Leopard_Seal t1_ivuqod8 wrote

Yeah there is a whole legend about them.

So the baobab was gods favorite but was also a bit needy. So they asked god for the thickest stem and god did give it to them. But they wanted even more and asked for the finest and nicest fruits, so god did also give them those. But the baobab, still wanting more, continued to ask for the most green and lush leaves. So god got a bit annoyed, ripped the tree out of the ground and planted it upside down again as punishment.

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Not_Leopard_Seal t1_irru494 wrote

>I’d always just assumed “that’s the colour of a maple leaf without the chlorophyll bits,” but I’m realizing now that that seems naive.

That's actually pretty much it. Leaves don't just have chlorophyll serving as an energy acceptor from sunlight but also other antioxidants in less concentration who accept energy from red and yellow, but also from green light unlike chlorophylls who accept red, yellow and violet light.

Here is the absorption spectra of chlorophyll A and B as well as Beta-Carotine. You'll notice that Beta-carotine absorpts quite a bit of green light.

Once it becomes fall, trees notice a change in the red light ratio during dusk and dawn and begin a process that is called "reverse clorophyll biosynthesis". Because chlorophyll is a very expensive molecule plants don't really degrade it. They save it from the leaves and suck it up into the wood, where it stays in a different form for the winter. That's why the leaves, now empty of chlorophyll, have this yellow and red color. Once the leaf loses the antioxidants as well, it becomes brown and dies. The chlorophyll will become active again in spring and will provide energy again in new leafs.

So the vibrant colors are not really a signal for anything. Just a change in light accepting molecules.

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