Question

Double fertilisation in angiosperms involves:

• A. One male gamete fusing with egg and another with synergid
• B. Two male gametes fusing with two eggs
• C. One male gamete fusing with egg and another with polar nuclei
• D. Fusion of antipodals with synergids

Hint:

Remember the "two for one" rule of double fertilization: two male gametes participate in two fusion events. One forms the embryo (zygote from egg + sperm), and the other forms the endosperm (primary endosperm nucleus from polar nuclei + sperm).

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks for the definition of "double fertilization" as it occurs specifically in angiosperms (flowering plants).

Step 3: Detailed Explanation:
Double fertilization is a unique and defining characteristic of angiosperms. It involves two separate fusion events occurring simultaneously within the embryo sac:
1. Syngamy (True Fertilization): One male gamete (sperm nucleus) fuses with the egg cell to form a diploid zygote. This zygote will develop into the embryo.
2. Triple Fusion: The other male gamete fuses with the two polar nuclei (which form a diploid central cell) to produce a triploid primary endosperm nucleus. This triploid nucleus will develop into the endosperm, a nutritive tissue for the developing embryo.
Therefore, option (C) correctly describes these two fusion events.
- Options (A) and (D) incorrectly involve synergids or antipodals in the fusion. Synergids and antipodals are part of the embryo sac but are not directly involved in the fusion processes of double fertilization.
- Option (B) incorrectly states fusion with two eggs.

Step 4: Final Answer:
Double fertilisation in angiosperms involves one male gamete fusing with egg and another with polar nuclei.