Question

Endosperm is formed during the double fertilization by:

• A. Two polar nuclei & one male gamete
• B. One polar nuclei & one male gamete
• C. Ovum and male gamete
• D. Two polar nuclei & two male gametes

Answer 1

The Correct Option is A

The question pertains to a fundamental process observed in the sexual reproduction of flowering plants – specifically, the formation of endosperm during double fertilization. Let's delve into the details:

1. Understanding Double Fertilization: Double fertilization is a unique and complex process that occurs in angiosperms (flowering plants). During this process, two male gametes from the pollen grain travel through the pollen tube to reach the ovule.
2. Role of Male Gametes: Out of the two male gametes, one fuses with the egg cell to form a zygote, which will develop into an embryo. The other male gamete is involved in the formation of the endosperm.
3. Formation of Endosperm: The second male gamete fuses with the two polar nuclei located within the central cell of the ovule's embryo sac. This fusion results in the formation of a triploid cell, which develops into the endosperm. The primary purpose of the endosperm is to provide nutritional support to the developing embryo.
4. Correct Answer Explanation: The correct answer is Two polar nuclei & one male gamete because the endosperm is indeed formed by the fusion of these three nuclei, resulting in a triploid (3n) tissue.
5. Elimination of Other Options:
   • One polar nuclei & one male gamete: This combination does not occur naturally in the process of double fertilization as described above.
   • Ovum and male gamete: This combination forms the zygote, not the endosperm.
   • Two polar nuclei & two male gametes: This does not accurately describe any known process in plant fertilization.

Thus, the endosperm is formed during double fertilization by the fusion of two polar nuclei and one male gamete, solidifying option Two polar nuclei & one male gamete as the correct choice.