Question

The endosperm is formed during the double fertilization by

• A. one polar nucleus and one male gamete
• B. two polar nuclei and one male gamete
• C. two polar nuclei and two male gametes
• D. ovum and male gamete

Answer 1

The correct option is B

two polar nuclei and one male gamete

The correct option is option B.

An explanation for the correct option:

1. One male gamete and two polar nuclei
2. Angiosperms are distinguished by double fertilization. It is made up of syngamy and triple fusion. The fusion of one male gamete (n) with an egg nucleus (n) results in the formation of a zygote (2n). Triple fusion occurs when the second male gamete (n) fuses with the two polar nuclei (n+n) present in the central cell.
3. The primary endosperm nucleus is formed as a result of the triple fusion (3n).

An explanation for the incorrect options:

Option A:

1. A zygote is formed when one of the male gametes fuses with one polar nucleus.

Option C:

1. two male gametes and two polar nuclei fuses and each pair of male gametes and polar nuclei form a zygote so two zygotes are formed.

Option D:

1. During fertilization, male and female gametes fuse to form a diploid (with paired chromosomes) zygote.

Final answer: An endosperm is formed when two polar nuclei fuse to one male gamete.