Question

During double fertilization in angiosperms, which of the following events occurs?

• A. Fusion of a sperm cell with the egg cell to form a zygote, followed by fusion of another sperm cell with the polar nuclei to form endosperm.
• B. Fusion of a sperm cell with the egg cell to form the endosperm, followed by fusion of another sperm cell with the polar nuclei to form a zygote.
• C. Fusion of a sperm cell with the egg cell to form a seed, followed by fusion of another sperm cell with the polar nuclei to form endosperm.
• D. Fusion of a sperm cell with the polar nuclei to form the zygote, followed by fusion of another sperm cell with the egg cell to form endosperm.

Hint:

Double fertilization ensures that resources in the ovule are directed toward a fertilized ovum, optimizing reproductive success in angiosperms.

Answer 1

The Correct Option is A

Step 1: Double fertilization, a characteristic of angiosperms, involves two simultaneous fertilization events.

Step 2: The two events are: 1. Fusion of one sperm cell with the egg cell, initiating zygote development into the embryo. 2. Fusion of the second sperm cell with the two polar nuclei in the central cell, creating a triploid structure that develops into the endosperm.

Step 3: Evaluation of alternative options.

- (B): Rejected. The endosperm originates from the polar nuclei, not the egg cell.

- (C): Rejected. Seed development involves the zygote and maternal tissues, not direct contribution from the sperm cell.

- (D): Rejected. The polar nuclei give rise to the endosperm, not the zygote.

Therefore, option (A) accurately outlines the sequence of events.