Introduction: Tissue culture is a technique used to grow cells or tissues in a controlled and sterile environment. In this process, cells are taken from a plant and grown in a culture medium to produce a callus.

Given: Pollen grains of a plant with 2n=28 are used for tissue culture.

Explanation:

- When pollen grains are cultured in a medium, they undergo mitosis to produce haploid cells called microspores.
- These microspores then divide by mitosis to produce a mass of undifferentiated cells called a callus.
- The cells of the callus are usually haploid because they are derived from the haploid microspores.
- However, in some cases, the cells of the callus may be diploid if the microspores undergo mitosis without completing meiosis, resulting in the formation of diploid cells.

Answer: The number of chromosomes in the cells of the callus would be (c) 14. This is because the pollen grains used for tissue culture had 2n=28 chromosomes, which means that they were diploid. However, during tissue culture, the cells of the callus are usually haploid. Therefore, the haploid cells of the callus would have 14 chromosomes, which is half of the diploid number of chromosomes in the pollen grains.

Conclusion: In summary, tissue culture is a technique used to grow cells or tissues in a controlled environment. When pollen grains are cultured, they produce a callus consisting of undifferentiated cells. The cells of the callus are usually haploid, and in this case, would have 14 chromosomes.

Plant with 2n=28 it means the pollen is having 14 chromosomal which is haploid if pollen grain is cultured the callus will also be haploid only