In Zea mays 20 chromosomes are present in the cell of shoot apex. The number of chromosomes in pollen grain, nucellus, polar nucleus and aleurone layer cells will be :

Ploidy of shoot apex cells-2n , pollen grains -n, nucellus-2n, polar nuclei n+n ,aleurone layer -3n . Diploid number of chromosomes in zea mays is 20 . If diploid number is 20 , haploid number would be 10 and triploid number would be 30 .so ploidy of pollen grain , nucellus ,polar nucleus and aleurone layer are 10 ,20,10 and 30 .