A total 168 pollen grains with 14 chromosomes in each pollen grains are released from a mature microsporangium. Mention the correct ratio of pollen mother cells and generative cells, vegetative cells and male gametes produced by microsporangium?
Answers
Answer:
Explanation:
No of PMC = 42
Generative cells and vegetative cells = 168
male gamete = 168
so the ratio is 1:4:4
at second celled stage
The required ratio is 1:4:4:8
Given:
There are 14 chromosomes in one pollen grain. The total pollen grain is 168.
To Find:
The ratio of pollen mother and generative cells, vegetative cells, and male gametes produced by microsporangium.
Solution:
We have, a total number of chromosomes in one pollen grain is 14.
The total number of pollen grains is 168.
4 pollen grains are generated from one pollen mother cell.
Thus the number of PMCs would be, 168/4 i.e, 42 PMCs.
Now, we know a pollen grain, which is also known as a microspore gets divided mitotically giving rise to two cells: A generative cell and a vegetative cell.
Thus the number of the generative and vegetative cells will be equal to the number of total pollen grains.
That means 168 each.
Again in 40 % of angiosperms, GC divides into 2 male gametes, and pollen is shed at 3 celled stages (1 vegetative and 2 male gametes).
Thus male gametes will double the number of total pollen grains, that is,
168 × 2 = 336 male gametes.
Thus the ratio stands as,
PMC : GC : VC : MG
= 42 : 168 : 168 : 336
=1 : 4 : 4 : 8
Thus the required ratio is 1:4:4:8.
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