Question

Nucleus of megaspore divides mitotically to form two nuclei which move to opposite poles and later form an embryo sac which is.

• A. $2$- nucleate
• B. $4$- nucleate
• C. $6$- nucleate
• D. $8$- nucleate

Answer 1

Answer: (D)

$8$- nucleate

During megasporogenesis, four megaspore are formed by from megaspore mother cell (MMC) by meiosis division. Out of the four megaspore, 3 degenerates and one remain functional. This functional megaspore divides mitotically into two, four and finally eight daughter nuclei. Four nuclei are located at each pole and one from each pole move to the centre to form secondary nucleus (two polar nuclei or central cell). This further fuses with second male gamete (brought by pollen tube) to form endosperm. Thus an angiospermic embryo sac is eight nucleate and 7 celled at maturity.
So, the correct option is D.