Question

A bisexual flower gives rise to 150 MMC and 250 PMC in a single season. How many mature embryo sacs and pollen grains will be formed by it over 10 seasons?

• A. 1500 embryo sacs, 10000 pollen grains
• B. 6000 embryo sacs, 2500 pollen grains
• C. 1500 embryo sacs, 2500 pollen grains
• D. 6000 embryo sacs, 10000 pollen grains

Answer 1

The correct option is A 1500 embryo sacs, 10000 pollen grains

One diploid megaspore mother cell - MMC, gives rise to four haploid megaspores. However, three of them degenerate and only one of them remains functional which goes on to develop into an embryo sac. As a result, one diploid MMC results in the formation of only one mature embryo sac. Since, the given flower gives rise to 150 MMC in a season, hence it will give rise to 150 x 10 i.e. 1500 mature embryo sacs over 10 seasons.

One diploid pollen mother cell (PMC) gives rise to four haploid microspores. All of them are functional and hence each of them gives rise to four haploid pollen grains in turn. Since, the given flower gives rise to 250 PMC in a season, hence it will give rise to 250 x 4 x 10 i.e. 10000 pollen grains over 10 seasons.