If the microspore mother cell of a beet plant contains 18 chromosomes, what will be the number of chromosomes in the cells of its perisperm and endosperm, respectively?

Step-by-step solution

The microspore mother cell (MMC) is a diploid cell ( 2n ). Given 2n = 18 , the haploid chromosome number ( n ) is 9. Perisperm is the residual persistent nucellus, which is a maternal diploid tissue. Thus, the ploidy of perisperm is 2n , and its cells will contain 18 chromosomes. The endosperm in angiosperms develops from the primary endosperm nucleus (PEN) formed by triple fusion. Thus, its ploidy is 3n , and its cells will contain 3 9 = 27 chromosomes. Therefore, the correct pair is 18 and 27. Answer: 18 and 27