Question

The other name of a secondary nucleus formed from two polar nuclei is ____.
a) Generative nucleus
b) Tube nucleus
c) Coenocytic nucleus
d) Endosperm

Answer 1

Double fertilization is a unique angiosperm feature of angiosperms which occurs when one male gamete fuses with the egg cell to produce diploid zygote while the other male gamete fuses with diploid secondary nucleus that produces endosperm.

Complete answer:
During the double fertilization in angiosperms, one of the two male gametes carried by the pollen tube fuses with the egg cell nucleus to form the diploid zygote, and the other with the diploid central cell nucleus to form endosperm. The initial stage in the development of endosperm is considered as cell proliferation, leading to formation of a syncytium composed of numerous free nuclei within the cytoplasm, enclosed in a single common membrane. As endosperm form by fusion of a diploid nucleus and a haploid gamete hence it is a triploid structure.
Among the given options:
Generative nucleus is one of the two haploid nuclei in an angiosperm pollen grain. It divides by mitosis to produce two male gamete nuclei.
Tube nucleus is one of the two haploid nuclei within a developing pollen tube whose function may be control of tube growth. It degenerates after double fertilization.
A coenocytic is a multinucleate cell which can be obtained from multiple nuclear divisions without their accompanying cytoplasmic divisions.
The endosperm is a nutritive tissue produced inside the seeds of most of the angiosperms following fertilization. The endosperm nourishes embryo development. and, in some species including cereals, stores food and represents a major source of food for humans and other animals.

So the correct answer is option C.

Note: During nuclear endosperm formation, primary endosperm nucleus (PEM) divides repeatedly without wall formation (cytokinesis) to produce a large number of free nuclei. Nuclear endosperm is the most common type of endosperm found in flowering plants. It is named so because it contains free nuclei initially.