Plant cells have components that are a little denser than the rest of the cell. These move downward in response to gravity, the cells notice this, and then produce hormones to grow in the opposite direction.
Wikipedia has a more complicated explanation here, in the statolith section of this article:
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Plant cells have components that are a little denser than the rest of the cell. These move downward in response to gravity, the cells notice this, and then produce hormones to grow in the opposite direction.
Wikipedia has a more complicated explanation here, in the statolith section of this article:
https://en.m.wikipedia.org/wiki/Gravitropism