Chapter 24, Problem 9STP

Summary Introduction

To write:

About the purpose of the given experiment

Introduction:

Hormones are organic compounds that are formed in one part of an organism and then transported to another part where they affect. It only takes a tiny amount of a hormone to cause an organism to change. Plant hormones can influence the response of a plant to its surroundings.

Explanation of Solution

The experiment given demonstrates a plant’s tropic responses. A tropism is a response to an external stimulus by the growth of a plant. It is said as positive tropism if the resulting plant growth is towards the stimulus. When the resulting growth of plants is away from the stimulus, it is considered to be negative tropism. The various types of tropism include phototropism, gravitropism, and thigmotropism.

The given experiment shows phototropism where the growth of plants reacted to light caused by an unequal distribution of auxin. On the side of the plant, there is less auxin toward the light source and more auxin to the side away from the source of light. The cells on the side away from the light elongate because of the presence of auxin that aids in cell elongation, making that side of the stem lengthier. It allows the stem to bend in the direction of the sun.

Conclusion

Therefore, the purpose of the given experiment is to show tropic responses of a plant toward the light.