Question

The habit of a cabbage plant can be changed drastically by the application of __________.
a. IAA
b. $GA_3$
c. Kinetin
d. ABA

Answer 1

There are different chemical compounds found in plants in very low concentrations which regulate growth, development, and different types of habits. They are known as plant hormones. There are different types of plant hormones such as auxins, gibberellins, cytokinin, etc. which play different roles in the plants.

Complete answer:
Plant hormones are a type of chemical compound that is produced in almost all parts of the plant and are transmitted to various parts of the plant. Plant hormones are the derivatives of indole, terpenes, adenine, carotenoids, and gases. The hormones found in plants in very low concentrations.

Hormones perform a crucial role in the process of growth and development of plants. It also regulates different types of plant habits. Plant hormones are helpful for vernalization, phototropism, seed germination, dormancy, etc. Auxin, Gibberellin, Cytokinin, ABA, etc are examples of plant hormones. Each of the hormones play a different role in the growth and development of the plant.

Cabbage is a rosette plant. This habit of cabbage can be changed drastically by the application of gibberellic acid or GA which helps in the longitudinal growth of the stem. Plant hormone gibberellic acid is responsible for bolting in plants which is the rapid elongation of a floral stalk. For the bolting of stems, either long days or cold treatment is required. But this bolting can be occurred artificially by the application of gibberellic acid under normal conditions.

IAA is a plant hormone that is a form of auxin present in plants. It regulates the growth and development processes such as cell division and elongation. It also responds to light, gravity, and pathogens. Kinetin is a type of cytokinin. It belongs to a class of plant hormone that promotes cell division. ABA or abscisic acid is referred to as an inhibitory hormone that is involved in the bud and seed dormancy.

Hence, the correct answer is option (B).

Note: There are different types of plant hormone found in plants which are present in very low concentration in plants. They play a different role in the plant. The rosette habit of cabbage can be changed drastically by the application of gibberellic acid or GA. Bolting in the plants is the rapid elongation of a floral stalk. It can occur naturally but applying gibberellic acid it can be done in normal condition.