Question

The pineapple which under natural condition is difficult to blossom has been made to produce fruits throughout the year by application of:

• A. Phenyl acetic acid
• B. NAA, 2, 4­-D
• C. IAA, IBA
• D. Cytokinin

Answer 1

The correct option is B

NAA, 2, 4­-D

The correct option is B.
The explanation for the correct option:

1. NAA is 1-Naphthalene Acetic Acid which exhibits auxin activity.
2. 2,4-D kills plants in 3 ways:
   1. By altering the plasticity of these cell walls.
   2. Increasing production of ethylene in plants.
   3. And, influencing protein synthesis.

The explanation for incorrect options:

Option A:

1. Phenylacetic acid(PAA) is a plant auxin that also has antimicrobial activity.

Option C:

1. IAA is l main auxin that regulates plant development & growth process by participating in tissue differentiation and responding to gravity and light.
2. IBA is the Indole-3-butyric acid, which induces rooting in stem cuttings of various kinds of plants.

Option D:

1. Cytokinins 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.

Final answer: The pineapple which under natural conditions is difficult to blossom has been made to produce fruits throughout the year by application of NAA and 2,4-D.