How many of the following statements about the endosperm are correct?
A. Most zygotes divide only after a certain amount of endosperm is formed.
B. In the most common type of endosperm development, the PEN undergoes successive nuclear divisions to give rise to free nuclei.
C. In the free-nuclear stage of the endosperm, each nuclear division is followed at once by cell wall formation.
D. The number of free nuclei formed before the endosperm becomes cellular varies greatly.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Three
After triple fusion, the primary endosperm cell develops into the endosperm. In the most common type, the primary endosperm nucleus (PEN) first divides many times without cell walls, giving a free-nuclear endosperm. Cell walls form only later, and the endosperm becomes cellular.
A. Most zygotes divide only after a certain amount of endosperm is formed. — True. This gives the embryo assured nutrition; endosperm development comes before embryo development.
B. In the most common type of endosperm development, the PEN undergoes successive nuclear divisions to give rise to free nuclei. — True. This stage is called free-nuclear endosperm.
C. In the free-nuclear stage of the endosperm, each nuclear division is followed at once by cell wall formation. — False. In the free-nuclear stage the nuclei divide without cell walls; cell wall formation occurs subsequently.
D. The number of free nuclei formed before the endosperm becomes cellular varies greatly. — True. NCERT states that the number of free nuclei formed before cellularisation varies greatly.
So three statements (A, B and D) are correct.
NCERT Extract:
Endosperm – “… 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.”
Embryo – “Embryo develops at the micropylar end of the embryo sac where the zygote is situated. Most zygotes divide only after certain amount of endosperm is formed. This is an adaptation to provide assured nutrition to the developing embryo.”