Corn root gravitropism

This movie shows the positive gravitropic response of a corn root after the seedling was placed on its side. Each images was taken at 5 min intervals. In about 20 to 30 min after being placed on its side (to see this advance the movie one frame at a time), gravitropism starts to cause differential growth along the root tip and the root begins to bend down. As more time passes, the root continues to get longer and curves more and more until it is finally reoriented so the tip faces down. Also not that the root wiggles (nutation) around a bit as it reorients, although the wiggling is not as dramatic as in the plant shoot (see other gravity movies).