Question

A hexaploid plant gets pollinated by octaploid plant as a result of double fertilisation what will be the ploidy of embryo and endosperm resp.

Answer 1

See due to meiosis the male octaploid will show 4 sets of chromosomes.

while the egg cell of hexaploid plant will show 3 sets of chromosomes. The polar nuclei while shows 6 sets.

The resulting zygote will have 4+3=7

and endosperm will have 4+6=10

therefore zygote is heptaploid while endosperm is decaploid.

Answer 2

We know that during gamete formation half of the chromosomes are transmitted to the next generation.

So in case of the tetraploid male plant (4n), the gamete will have half the number of chromosomes i.e. 2n

Similarly in case of the hexaploid female plant (6n), the gamete will have have the number of chromosomes again i.e. 3n

Therefore upon fusion of gametes containing 2n and 3n chromosomes, the offspring gets a ploidy level of 2n+3n=5n.

Hope this helps!