Which of the following statements is incorrect regarding endosperm in flowering plants?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → The endosperm nucleus is diploid.
In double fertilisation one male gamete fuses with the egg (syngamy) and forms the diploid zygote. The other male gamete fuses with the two polar nuclei in the central cell. This fusion of three haploid nuclei is triple fusion, and its product is the triploid primary endosperm nucleus. The endosperm grows from it.
Option (1) The endosperm provides nutrition to the embryo. — A correct statement. The endosperm cells are filled with reserve food. This food is used for the nutrition of the developing embryo.
Option (2) The primary endosperm cell divides repeatedly and forms a triploid endosperm tissue. — A correct statement. The primary endosperm cell divides again and again. Every cell keeps the three sets of chromosomes of the primary endosperm nucleus, so the endosperm tissue is triploid.
Option (3) The endosperm nucleus is diploid. — An incorrect statement. The endosperm nucleus comes from two polar nuclei and one male gamete, so it is triploid (3n), not diploid. The diploid product of double fertilisation is the zygote.
NCERT Extract:
Double Fertilisation – “… The other male gamete moves towards the two polar nuclei located in the central cell and fuses with them to produce a triploid primary endosperm nucleus (PEN) (Figure 1.13a). As this involves the fusion of three haploid nuclei it is termed triple fusion.”
Endosperm – “Endosperm development precedes embryo development. … The primary endosperm cell divides repeatedly and forms a triploid endosperm tissue. The cells of this tissue are filled with reserve food materials and are used for the nutrition of the developing embryo.”