Question

Which hormone is responsible for apical growth?
A. IAA
B. Abscisic acid
C. GA
D. All of the above

Answer 1

Hint: Hormones are a kind of chemical that flow throughout the body to convey messages from one place to another and thus establish a strong communication between various parts of the body.

Complete Answer
Let's study each of the options mentioned above to find the correct answer.
a) IAA stands for 'Indoleacetic acid'. It is a kind of hormone that is released in newly growing plant parts such as leaves or germinating buds. This hormone promotes apical growth of the plant by suppressing the tendencies of its lateral growth. Since, it is responsible for apical growth of plants, so can be considered as the correct answer to the question.
b) Abscisic acid is a hormone released in the plant body. This hormone is concerned with development and maturation of seeds and making the plant body strong enough to withstand the environment stresses. Since, it is not concerned with apical growth of plants so cannot be considered as the correct answer.
c) GA stands for Gibberellic Acid. It is also one of the hormones released in the plant body. Its main function is to manage the development of plants. Since, it is not concerned with apical growth of plants so cannot be considered as the correct answer.

So, the correct answer is ‘IAA.’

Note:
The topmost growing part of the plant body is called its apical region. This region consists of meristematic tissues that are capable of inducing rapid growth of plant body parts in terms of size. This happens under the influence of a hormone released by the plant itself.