Question

Which one prevents premature fall of fruit?
A) NAA
B) Ethylene
C) GA3
D) Zeatin

Answer 1

Hint:Presence of fruit is the characteristic feature of angiosperms. Fruits are the mature ovary and its associated parts. Fruit usually contains seeds which have developed from the enclosed ovule after fertilization.

Complete answer:
>NAA: NAA stands for Naphthaleneacetic acid. It is an organic compound.It is a synthetic plant hormone in the auxin family. NAA is the rooting agent.It is used for the propagation of plants from stem and leaf cutting. NAA is also used for plant tissue culture.This hormone is also used to prevent premature fall of fruit. The hormone NAA is toxic to the plants in high concentration.NAA is widely used in agriculture for various purposes.
>Ethylene: Ethylene is an unsaturated hydrocarbon i.e. alkene which naturally act as plant hormone.
It acts as trace levels throughout the life of the plant.It stimulates or regulates the ripening of fruit, the opening of flowers and shedding of leaves.
>GA3: GA3 is a plant hormone which is also known as gibberellic acid. It is the hormone which is found in the plants and fungi. When the gibberellic acid purifies, it appears white to pale-yellow solid.
Giibberlic acid promotes growth and elongation of cells.It affects decomposition of plants and helps plants to grow.They are produced in large amounts in the normal condition of plants.
>Zeatin: Zeatin is the cytokine which is derived from the adenine.It also promotes the growth of lateral buds.They also stimulate cell division to produce bushier plants when sprayed on the meristems. Zeatin with auxin promotes callus initiation. It can be applied to stimulate seed germination and seedling growth.
Therefore, it has been clear from the above discussion NAA prevents premature fall of fruit.

Hence, option D is the correct answer.

Note: Plant hormones are the signaling molecules that are produced by the plants. They occur in extremely low concentrations. Plant hormones control all aspects of plant growth, pathogen defense, stress tolerance, etc. The word phytohormone which means plant hormone was coined by Went and Thimann.