I saw this tree in front of my room with those branches, and I asked myself why they didn’t grow downward in the direction of gravity since that would be easy for them? And I came to the conclusion that they are seeking sunlight. Is there any research which explain how they can do that?

I found that this mechanism is called Gravitropism (Tree Branches grow against gravity, while roots grow into the soil in the direction of gravity) but I didn’t find a clear explanation.

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1 Answer 1


This review paper might help answer your question: http://www.plantphysiol.org/content/120/2/343.full

It seems that starch-filled organelles called amyloplasts sediment in the cell according to the pull of gravity, and in doing so this gives the cell some form of basic up-down polarisation. If my memory serves correctly, this can then cause changes to the growth of the cell in the branches, meaning the side of the cell opposite the amyloplasts grows slower and the side closest the amyloplasts grows faster, causing the upwards curvature of the branches seen in your tree.


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