How do roots know which way is down?
Falling Stones, Rising Roots
How do roots know which way is down?
Plant a seed in dirt, walk away, come back in a week. The root punches down, the shoot climbs up. Every single time. No eyes, no brain, no GPS. So how does the root know which way is down?
Inside every root tip, thousands of tiny cells are packed with even tinier grains called statoliths. They're dense little pellets, heavier than water, heavier than the cell juice around them. And gravity pulls on heavy things.
