Experiments on the positive phototropic response of plants indicate that ________.
A) light destroys auxin
B) auxin moves down the plant apoplastically
C) auxin is synthesized in the area where the stem bends
D) auxin can move to the shady side of the stem

Question

Quizplus · Accepted Answer

The positive phototropic response of plants is due to the differential distribution of auxin, which moves towards the shaded side of the stem. This promotes elongation of cells on that side, resulting in bending towards the light source. Therefore, option D is correct. Option A is not correct as light does not destroy auxin, but rather it affects its distribution. Option B is not correct as auxin moves through the plant both apoplastically and symplastically. Option C is also not correct as auxin is synthesized in the shoot apical meristem and young leaves, not just in the area where the stem bends.

Experiments on the Positive Phototropic Response of Plants Indicate That