Question

A plant hormone responsible for shoot formation is

• A. Auxin
• B. Ethylene
• C. Cytokinin
• D. Jasmonic acid

Answer 1

The correct option is C

Cytokinin

The correct option is C.

Explanation of correct option:

1. Cytokinins: They are produced in regions where cell division generally occurs; mostly in the roots and shoots.
2. Functions of Cytokinins:
   1. Break bud & seed dormancy.
   2. Promotes growth of lateral bud.
   3. Promotes cell division & apical dominance.
   4. They are also used to keep flowers fresh for a longer time.

Explanation for incorrect options:

Option A:

1. Auxins are one of most important plant hormones.
2. The chief naturally occurring auxin is an indole-3 acetic acid – IAA and other related compounds.
3. Functions of the Auxins:
   1. Facilitate flowering in the plants.
   2. Used in process of plant propagation.
   3. Used by gardeners to keep the lawns free from weeds.
   4. Involved in initiation of roots in stem cuttings.
   5. Prevention of dropping of the leaves and fruits at early stages.
   6. Regulate xylem differentiation & assists in cell division.
      

Option B:

1. Ethylene: Ethylene is a group of plant growth regulators that are widely used for the purpose of ripening fruits and for the production of more flowers and fruits.
2. Functions:
   1. It regulates a number of physiological processes thus used as a plant growth regulator.
   2. Ethylene lamps could be used for colour development and for the ripening of fruits such as banana, mango, apple, etc.
   3. It also induces a feminising effect in plants, which means used to increase the number of female flowers in a plant to induce fruiting.
   4. It is applied to rhizomes, tubers and seeds to induce early sprouting in them.

Option D:

1. Jasmonic acid is a growth regulated compound also known as stress hormone in higher plants.

Final answer: A plant hormone responsible for shoot formation is cytokinin.