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

Question

Quizplus · Accepted Answer

Experiments show that the positive phototropic response of plants is due to the movement of auxin from the bright side of the stem to the shady side. This mechanism is known as the redistribution hypothesis. Therefore, choice D is correct. Choice A is incorrect because light actually stimulates the synthesis of auxin. Choice B is incorrect because auxin moves through the plant in a polar manner, meaning it moves from cell to cell through plasmodesmata rather than through the apoplast. Choice C is incorrect because auxin is not synthesized in the area where the stem bends, but rather it is synthesized in the apical meristem and young leaves.

Experiments on the Positive Phototropic Response of Plants Indicate That