Question

When a diploid female plant is crossed with tetraploid male the ploidy of endosperm cells in the resulting series?

Answer 1

The ploidy of endosperm cells in resulting seed is tetraploidy, when a diploid female plant is crossed with tetraploid male.

Explanation:

The condition given in the question is diploid female is crossing with a tetraploid male.

It means that female is in 2n condition whereas male is in 4n condition. After meiosis reduction the gametes formed were n condition of female  and male is in 2n condition. When these two gametes fuses, they tends to form zygote which is triploid (3n) in condition.

For endosperm formation triple fusion occurs in which “two polar nuclei and one male gamete” fuses with each other. Here the polar nuclei are in haploid (n) condition and male gamete is in diploid (2n) condition. Hence the fusion is n+n+2n = 4n.  Hence the resultant is tetraploid male.