Question

The phenomenon of double fertilization

• A. involves the formation of an embryo only
• B. involves the formation of an endosperm only
• C. is a characteristic feature of gymnosperms
• D. involves five nuclei

Answer 1

The correct option is D involves five nuclei

Double fertilization is a characteristic feature of angiosperms. It includes both syngamy and triple fusion.

Syngamy: Fusion of a male gamete with a female gamete to form a zygote that in turn develops into an embryo.

Triple fusion: Fusion of one male gamete with the diploid secondary nucleus (formed by fusion of two haploid polar nuclei) results in the formation of triploid primary endosperm nucleus (PEN). PEN divides and forms the triploid nutritive tissue, endosperm.

Hence, five nuclei are involved in double fertilisation. Two nuclei of male gametes, two polar nuclei and one nucleus of egg.

In case of fertilization in gymnosperms, only fusion of male gamete and female gamete happens, unlike angiosperms. There is no event of triple fusion taking place here and the endosperm formed is haploid.