Question

ASSERTION (A): Female gametophyte in Angiosperm is 7-celled and 8-nucleate.

REASON (R): Double fertilisation occurs in Angiosperm.

(a) Both A and R are true, and R is the correct explanation of A.

(b) Both A and R are true, but R is not the correct explanation of A.

(c) A is true but R is false.

(d) Both A and R are false.​

Answer 1

Both A and R are true, and R is the correct explanation of A.

When the pollen tube gerninates on the stigma of a carpel, two pollen grains descend to the ovary, and they enter through the micropylar end.

• One of the pollen fuses with the egg cell to form a diploid zygote.
• While the other pollen fuses with the central cells (two polar nuclei) to form a triploid primary endosperm nucleus.

Further, the zygote develops into an embryo and the PEN develops into Endosperm cells.

• Endosperm is nutritive and supportive in function, it nourishes the growing embryo.

Answer 2

Question:-

ASSERTION (A): Female gametophyte in Angiosperm is 7-celled and 8-nucleate.

REASON (R): Double fertilisation occurs in Angiosperm.

• (a) Both A and R are true, and R is the correct explanation of A.
• (b) Both A and R are true, but R is not the correct explanation of A.
• (c) A is true but R is false.
• (d) Both A and R are false.

Answer:-

• Option A) Both A and R are true, and R is the correct explanation of A.

Explanation:-

• Female gametophyte or the embryo sac in Angiosperms is eight nucleate type, where a single megaspore divides mitotically to form the eight nucleate, seven celled type.
• Double fertilization occurs as two male gametes released are released from the pollen tube, one fuses with the egg to form the diploid zygote and the other with the diploid central cell to form the triploid endosperm nucleus.

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