Ploidy level of Nucellus, Endosperm, Polar nuclei, Megaspore mother cell, female gametophyte respectively are (A) 2n,3n,n,2n,n (B) 2n,3n,2n,n,n (C) n,2n,n,2n,n (D) 2n,3n,2n,2n,n

Question:

Ploidy level of Nucellus, Endosperm, Polar nuclei, Megaspore mother cell, female gametophyte respectively are 

(A) 2n,3n,n,2n,n 

(B) 2n,3n,2n,n,n 

(C) n,2n,n,2n,n 

(D) 2n,3n,2n,2n,n

Answer: Correct option (A)  2n,3n,n,2n,n 

Explanation:

• Nucellus, microspore mother cells (MMC), and megaspore mother cells are part of sporophyte so these are diploid cells and their ploidy is 2n. And female gametophytes are part of gametophyte and ploidy is n. 
• The endosperm constitutes an organism separate from the growing embryo. About 70% of angiosperm species have polyploid endosperm cells. These are typically triploid but can vary widely from diploid (2n) to 15n.
• Sperm released fuses with the two polar nuclei forming a triploid cell that develops into the endosperm.
• A megaspore mother cell is a diploid cell in which meiosis occurs, resulting in the production of four haploid megaspores.
• Hence, Ploidy level of Nucellus, endosperm, polar nuclei, Megaspore mother cell, female gametophyte respectively are 2n,3n,n,2n,n.
• So, the correct answer is '2n,3n,n,2n,n'.

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