Question

The number of meiotic division needed to produce 50 seeds are
A) 63
B) 50
C) 100
D) 200

Answer 1

Hint: Meiotic division is also called equational division. In this type of division, haploid somatic cells (egg and sperm) fuse together to form a zygote which is a diploid.

Complete answer:
To produce the seeds, a plant needs pollen and eggs and their fusion.
Therefore, Meiotic division of seed = Meiotic division of pollen grains + Meiotic division of eggs

For pollen grains,
4 pollen grains are produced after 1 meiotic division in 1 pollen sac
4 pollen grains $=$ 1 meiotic division
Hence, to produce 1 pollen grain $={\displaystyle \frac{1}{4}}$ meiotic division
For production of N pollen grains $=$ N pollen grains $={\displaystyle \frac{N}{4}}$ meiotic divisions

For eggs,
1 egg is produced after 1 meiotic division in megasporangium
1 egg $=$ 1 meiotic division
For production of N eggs, N eggs $=$ N meiotic division

For production of seeds,
N seeds $=N+{\displaystyle \frac{N}{4}}$Meiotic divisions
As per the data given in the question, the solution would be
The number of seeds $=50$
The number of meiotic divisions $=$

For 50 pollens $={\displaystyle \frac{50}{4}}$ meiotic divisions
For 50 eggs $=$ 50 meiotic divisions
Total: $=50+{\displaystyle \frac{50}{4}}={\displaystyle \frac{(50\times 4)+50}{4}}={\displaystyle \frac{200+50}{4}}={\displaystyle \frac{250}{4}}$ $=62.5\simeq 63$meiotic divisions.

Thus the correct answer is option ‘A’ which is 63 meiotic divisions.

Note: In spermatogenesis, 52 sperm can be produced in 13 meiotic divisions. Each meiotic division will give rise to four progeny. Please remember that,
i) For pollen grains, 1 meiotic division = 4 pollen grains
ii) For eggs, 1 meiotic division = 1 egg
iii) For seeds = meiotic division of pollen grains + meiotic division of eggs