JAMB Biology 1980 Question 40

Question 40

Plant Responses and Hormones

The tips of some rice seedlings were cut off while some were left intact. Both were covered with a container which had only one small hole to allow light through. After twenty-four hours it was observed that

  1. A.the cut tips bent away from light
  2. B.the cut tips bent towards source of light
  3. C.the intact tips bent away from the light
  4. D.the intact tips bent towards light
  5. E.both tips bent away from light.
Show the answer and explanation

Answer: D (the intact tips bent towards light)

Explanation

The tip detects light and produces the auxin that causes bending, so only intact seedlings bend towards the light.