Read the passage carefully and answer the questions based on the passage:
Pollen pistil interaction involves all events from the landing of pollen grains on the stigma until the pollen tube enters the embryo sac (when the pollen is compatible). When a pollen tube grows through the style and enters into the ovules, it finally discharges two male gametes in one of the synergids. Syngamy and triple fusion are two fusion events occur in angiosperms. Thus, angiosperms exhibit double fertilization. The products of these fusions are the diploid zygote and triploid primary endosperm nucleus. Zygote develops into embryo and primary endosperm cell forms the endosperm tissue. The developing embryo passes through different stages before maturation.
The coconut water from tender coconut, a good source of nutrition is nothing but:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Free-nuclear endosperm
The endosperm is the food tissue formed from the triploid primary endosperm cell. In the common type, the PEN first divides many times without forming walls. This gives a free-nuclear endosperm, with many free nuclei. Later walls form and the endosperm becomes cellular. In a coconut both stages can be seen at once.
Option (1) Free-nuclear endosperm — Correct. Coconut water holds thousands of free nuclei. The white kernel around it is the cellular endosperm.
Option (2) Synergids — Incorrect. The synergids are two cells of the egg apparatus. They break down after fertilisation.
Option (3) Antipodal cells — Incorrect. The antipodals are three cells at the chalazal end of the embryo sac. They also break down after fertilisation.
Option (4) Scutellum — Incorrect. The scutellum is the single cotyledon of grasses. It is part of the embryo, not the endosperm.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Endosperm – “Endosperm development precedes embryo development. Why? 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. In the most common type of endosperm development, the PEN undergoes successive nuclear divisions to give rise to free nuclei. This stage of endosperm development is called free-nuclear endosperm. Subsequently cell wall formation occurs and the endosperm becomes cellular. The number of free nuclei formed before cellularisation varies greatly. The coconut water from tender coconut that you are familiar with, is nothing but free-nuclear endosperm (made up of thousands of nuclei) and the surrounding white kernel is the cellular endosperm.”