What is the name of the substance that influences trophic growth movement of roots and shoots?

The unequal distribution of auxin on the shoot's side facing light and its side away from light causes the phototrophic movements of the shoot.

Auxin is produced at the apex of the shoot and travels downward.

The auxin concentration in the shoot changes on the side facing the light and the side away from the light when it is exposed to unidirectional light.

As a result, the concentration of auxin is higher on the side away from the light than it is on the side exposed to light. Auxin oxidizes on the side exposed to light and partially migrates to the other side to prevent its oxidation.

Cell elongation is brought about by auxin; as a result, the shoot bends in the direction of the light.

Similar to this, unequal auxin distribution brought on by gravitational pull is also responsible for the geotropic responses of shoot and root. When a plant is positioned horizontally, its lower side has a higher auxin concentration than its upper side.

Increased auxin concentration causes the shoot to bend away from gravity and the root to bend towards it, promoting growth in the shoot region and retarding growth in the root region.

The substance that influences trophic growth movement of roots and shoots is called auxin.