Question

Which of the following prevents falling of fruits?
A. GA 3
B. NAA
C. Ethylene
D. Zeatine

Answer 1

Hint: Plant hormones are signal providing molecules that are produced by plants. These are produced at very low concentrations and have widespread effects on the plant body. Some of these hormones promote cell elongation, phototropism, etc. while some of them are involved in seed dormancy, germination, etc.

Complete answer: NAA or Naphthalene Acetic Acid, which is a synthetic auxin, is a plant hormone that is produced artificially. This hormone prevents abscission; which is the natural process of detachment of parts from the plant like flowers and fruits. It prevents the formation of an abscission layer which prevents the process of abscission. Considering other options, GA 3 or Gibberellic Acid regulates the growth of plants. They stimulate stem and root development. In some plants, it induces mitotic division in the leaves and increases the rates of seed germination. Ethylene plays an important in inducing leaf senescence, which can trigger this process. It also induces the process of ripening of fruits. It also stimulates the opening of the flowers. Zeatin is a cytokinin which is derived from adenine. It is a major component present in coconut milk and it promotes plant growth. It also promotes the growth of lateral buds and the division of cells. It also prevents the yellowing of the vegetables and promotes the callus initiation when combined with auxin.
Hence, the correct answer is Option B

Note: Plant hormones help plants in tolerating environmental stress factors. It also controls plants growth and development, defence against pathogens, reproductive development, embryogenesis, and regulation of the organ size. Plant hormones are also called plant growth regulators.