Question

1. When auxin promotes stem curvature in response to directional light, it does so by
   1. being produced at the location of curvature to promote cell elongation on the shaded side
   2. being produced at the location of curvature to promote cell elongation on the illuminated side
   3. migrating along the illuminated side of the stem to promote cell elongation on the shaded side
   4. migrating along the illuminated side of the stem to promote cell elongation on the illuminated side
   5. migrating along the shaded side of the stem to promote cell elongation on the shaded side
   6. migrating along the shaded side of the stem to promote cell elongation on the illuminated side

Answer 1

Ans) The correct answer is "E" i.e migrating along the shaded side of the stem to promote cell elongation on the shaded side

(Auxin is diffused to the shaded side so that the cell division and cell elongation can occur and once the cell elongation occurs to a great extent on the shaded side, the result is the stem curvature towards the sunlight.It was observed that when the mica was inserted into the stem,the diffusion of auxin didnot occur to the shaded side and thus there was no bending towards the sunlight.This suggests that the auxin migrates to the shaded side and not at the illuminated side).