Planetagarden
In a plant cell, gravity pulls them to the "bottom," and once they find a resting place, they can send signals to neighboring cells in the plant essentially saying, "OK guys! We now know where Down is. Those of you that need to go down (root cells), go this way! ... They use little statolith balls as gravity receptors.
- What is the term used to describe how a plant knows which way is up or down?
- Which way is up and down?
- How do roots know which way to grow?
- How do plants grow upwards?
What is the term used to describe how a plant knows which way is up or down?
All plants can sense the direction of the gravitational field and orientate themselves accordingly. This is called geotaxis.
Which way is up and down?
There is an up and down in space. "Down" is simply the direction gravity is pulling you, and "up" is just the opposite direction. Since there is gravity everywhere in space, there is also an up and down everywhere in space.
How do roots know which way to grow?
If they come across some obstacle, they feel their way around it until they come to a point where they can grow again. The roots do this through a self-reinforcing chemical cycle. A protein at the tip of the root hairs, called RHD2, produces free radicals that stimulate the uptake of calcium from the soil.
How do plants grow upwards?
Paul - Plants grow upwards because they're trying to get to the light to begin photosynthesis, but mostly germinate underground where there's little light to follow. And so, the plants actually use gravity to tell it which way is up. They will grow upwards even in complete darkness.
