Types of cells in 2 celled pollen grains are ________.

Concept:

• Pollen grains are the male gametophytes of higher plants.
• They develop from microspores that are formed from pollen mother cells by meiosis.
• Thus pollen grains are haploid in nature.
• They are mostly spherical in shape and about 20-25µm in diameter.

Important Points

• Pollens undergo mitotic divisions to form one vegetative cell and one generative cell.
• Pollens are usually shed at this 2-celled stage.
• Vegetative cell -
  • It is used as a food reserve for the developing male gametes and may also be called as tube cell.
• Generative cell -
  • It is smaller in size compared to the vegetative cell and floats in the cytoplasm of the vegetative cell.
  • It is a spindle-shaped cell that undergoes mitosis to form 2 male gametes.

Additional Information

• In Angiosperms, the embryo sac is the female gametophyte, which is formed from a single megaspore.
• The embryo sac is 8-nucleate and 7-celled at maturity.
• It consists of the following cells:
  • Antipodal cell - There are 3 of these uninucleate cells present at the chalazal end that degenerate after fertilization.
  • Central cell - It is centrally located covering most of the embryo sac and contains 2 polar nuclei.
  • Egg cell - It is the female gamete that undergoes fusion with a male gamete.
  • Synergids - There are 2 synergid cells at the micropylar end with the filiform apparatus at their base.
• Filiform apparatus - consists of finger-like projections that assist the entry of pollen tube into the embryo sac.