If the meiocyte of a maize plant contains 20 chromosomes. Write the number of chromo.-some in the endosperm nad embryo of the maize grain and give reasons in support of your answer.
If the number of chromosomes in maize is 20, then maize is diploid in a nature 2n=20 chromosomes in embryo. So 30 chromosomes will be present in the endosperm. It is fact that the endosperm of angiosperms are triploid in nature i.e. 3n.
`2n=20`
`n=(20)/(2)=10`
Therefore, endosperm : `3n=10xx3=30`
Embryo : `2n=10xx2=20`
Reasons : `*` The union of two male gametes with different nuclei of the embryo sac is termed as double fertilization.
`”Egg (n) + Male gamete (n) Zygote (2n)”underset(“Zygote (2n)”)overset(“Syng amy”)rarr “Embryo”`
`*`Secondary nucleus(2n) + Male gamete (n) `underset(“triplofusion”)rarr`Primary Endosperm nucleus(3n) `rarr` Endosperm
No. of chromosomes in endosperm=30
No. of chromosomes in embryo=20
Endosperm is formed by primary endosperm nucleus which results from triple fusion ( fusion of one male gamete with the secondary nucleus ) whereas embryo is formed from zygote which is formed by syngamy.