Pollen grain(2n) , nucellus( n+n), perisperm ( 2n), endosperm(3n), embryosac(n) , megaspore( 2n)..

Ploidy of Different Plant Structures:

- Pollen Grain: The pollen grain is the male gametophyte in angiosperms. It is produced in the anther of the flower. The ploidy of the pollen grain is haploid (n). It contains half the number of chromosomes as compared to the somatic cells of the plant, representing the gametic phase of the life cycle.

- Nucellus: The nucellus is a part of the ovule, which is the female reproductive structure in flowering plants. It surrounds the megasporangium, where the megaspore mother cell is located. The ploidy of the nucellus varies depending on the specific stage of development. Initially, it is diploid (2n) because it arises from the diploid tissue of the sporophyte. However, during the process of megasporogenesis, the nucellus degenerates, and only a small part of it persists.

- Perisperm: The perisperm is a nutritive tissue found in some seeds. It develops from the nucellus and functions to provide nourishment to the developing embryo. The ploidy of the perisperm is also diploid (2n) since it arises from the diploid nucellus tissue.

- Endosperm: The endosperm is another nutritive tissue found in seeds. It develops as a result of double fertilization in angiosperms. The ploidy of the endosperm can vary depending on the species. In most cases, it is triploid (3n) because it is formed by the fusion of one sperm nucleus with the two polar nuclei in the central cell of the female gametophyte.

- Embryo Sac: The embryo sac, also known as the female gametophyte, is located within the ovule of flowering plants. It is the structure where fertilization takes place. The ploidy of the embryo sac is haploid (n). It is formed through the process of megagametogenesis, which involves meiosis of the megaspore mother cell to produce four haploid megaspores. Only one of these megaspores survives and develops into the mature embryo sac.

- Megaspore: The megaspore is a haploid spore that gives rise to the female gametophyte. It is formed through the process of megasporogenesis, which involves meiosis of the megaspore mother cell. The ploidy of the megaspore is haploid (n).

In summary, the ploidy of the pollen grain, embryosac, and megaspore is haploid (n). The nucellus and perisperm are diploid (2n), while the endosperm is triploid (3n). Understanding the ploidy of these different plant structures is essential for comprehending various aspects of plant reproduction and development.