Antipodal cells are haploid.
Antipodal cells are part of the female gametophyte (also known as the embryo sac) in flowering plants (angiosperms). Understanding their ploidy level requires a brief review of plant sexual reproduction.
-
Meiosis: Megasporogenesis in the ovule involves a megaspore mother cell undergoing meiosis. This produces four haploid megaspores.
-
Megagametophyte Development: Typically, only one of these haploid megaspores survives and develops into the megagametophyte or embryo sac. This surviving megaspore undergoes mitotic divisions without cytokinesis, leading to a multinucleate cell. Subsequent cellularization results in the formation of distinct cells.
-
Cellular Organization: The mature embryo sac typically consists of:
- Egg Cell: One haploid egg cell.
- Synergids: Two haploid synergid cells that flank the egg cell and play a role in pollen tube guidance.
- Central Cell: A large central cell containing two polar nuclei (which may or may not have fused yet). These nuclei are haploid individually, but after they fuse, the central cell becomes diploid prior to fertilization.
- Antipodal Cells: A group of usually three cells located at the opposite end of the embryo sac from the egg apparatus. These antipodal cells are haploid.
Therefore, since the antipodal cells originate from the haploid megaspore and undergo mitotic divisions, their nuclei contain only one set of chromosomes, making them haploid. Though their function isn't fully understood, they are believed to play a role in providing nutrients to the developing embryo sac.
