Definition - What does Gravitropism mean?
Gravitropism is a plant's natural growth response to the effects of gravity. Typically, roots grow down into the ground, and the stems and leaves grow up above the ground. However, when a plant is placed on its side, it will begin to automatically bend back in an upright position. This is the result of the chemical reaction of gravitropism.
MaximumYield explains Gravitropism
Gravitropism occurs when a plant hormone called auxin is triggered to automatically help the plant respond to the effects of gravity.
If a plant is laid on its side, the auxin concentration increases along the lower sides of the roots and stems and the plant’s response will be to return to the upward position. Auxin stimulates cell elongation on the stem portion, which instinctively makes the plant bend back up toward the sky, no matter what position it is placed in.
The auxin prohibits cell elongation in the roots, which causes the roots to bend down into the soil. In nature, if a plant is bent to the ground from the effects of wind or if it is damaged by a falling stick or branch, it will eventually grow back in an upward position, without any help from the gardener, because of gravitopism.