Question

One of the commonly used plant growth hormone in tea plantations is
A. Indole-3-acetic acid
B. Ethylene
C. Abscisic acid
D. Zeatin

Answer 1

Hint: Plant growth hormones are chemical substances that are involved in the regulation of growth, differentiation, and development of the plant. The growth hormones can be promoting type or inhibiting type. The growth hormone that promotes tea plantation is an example of the most abundant type of plant hormone called auxin.

Complete answer: The plant growth hormones or plant growth regulators are chemical molecules or messengers that act as key regulators in the growth, development, and senescence of plants. The promoting type of growth hormone helps in plant growth and elongation. On the other hand, the inhibiting type of plant growth hormone inhibits plant growth. Auxin is the most abundant promoting plant growth hormone. They are a weakly acidic hormone that promotes cell elongation, especially in the shoots. They were the first to be discovered. They are majorly found in shoot apices, leaf primordial, and developing seeds. Indole-3-acetic acid is an example of an auxin hormone. Like auxins, it promotes growth and cell elongation in plants. In tea plantations, cutting is performed followed by vegetative propagation. The cutting leads to the production of new stems and roots. The Indole-3-acetic acid is thus used in stem cuttings to promote stem growth. So, this is the right answer. Indole-3-acetic acid is applied as a plant growth hormone in tea plantation.
Ethylene, Abscisic acid, and Zeatin are not used in tea plantations, due to the following reasons.
-Ethylene is involved in the determination of the sex of flowers in plants. It is used in enhancing pollination and root development. Also, it stimulates fruit ripening.
-Abscisic acid is an inhibiting type plant growth regulator. It promotes senescence in plants. It regulates the stomatal opening and prevents evaporation from the plant.
-Zeatin is a type of cytokinin. Cytokinins are involved in the regulation of cell division.
Therefore, option A is the correct answer.

Note: In India, the Assam tea plantation is the first tea plantation. It is produced in two flushes. The other classes of auxins are also sometimes used to enhance the yield and quality of plants. Auxins are also used in tissue culture techniques. Many other plant hormones are also used in the growth promotion of plants.