If you are suspended in the air with your eyes closed and asked to point to the ground, in most cases you will be accurately able to do so. This is because human beings have miniscule crystalline stones in our ear cavities. They float here when we are suspended in the air and sink in when they sense gravity.

This allows us to know what side is up and down based on how the crystalline stones sink into the ear cavities. Plants can also sense gravity and always plant their roots in the direction of the gravitational pull they experience. Given the fact that they do not have ears or crystalline stones in those ears, how do they sense gravity?

This is what botanists at Miami University in Ohio led by John Kiss are trying to figure out. Plant roots have dense, ball like cells at the tip of their roots which are called statoliths. That is Greek for stationary stone. Professor Kiss feels that the statoliths are gravity receptors of the plants.

His idea was supported when they hit upon using a few plants on the international space station to check if the claim was valid. Sure enough with nearly zero gravity on the International Space Station the cells could not figure out which way was down and the roots just tend to float around in the air. Now that’s a science experiment that gives an interesting visual result.