Is auxin inactive at the shoot tip or does it cause elongation (or any other function) there?
Sunlight eradicates auxin, meaning that the part of the shoot tip of the plant which is receiving direct sunlight will have the least amount of auxin. The shoot tip is responsible for directional movement by the plant in response to sunlight, as this is the area where auxins can be found. No matter what the concentration, auxins promote growth in the shoot area of a plant (though higher concentrations promote growth more) .
You have rated this answer /10