Microsporogenesis

The Anther is the site of Microsporogenesis.

Densely cytoplasmic, Sporogenous Cells develop within the Anther.

The Sporogenous Cells become separate and enter Meiosis.

Sporogenous Cells At late Prophase, early Metaphase of the first Meiotic Division.

Telophase of the First Meiotic Division for Sporogenous Cells

Two Haploid Cells are the result of this process.These Divide again to produce four haploid cells.

The haploid cells form a sphere called a Tetrad. Notice that the chromatin is still condensed in the Nucleus of each tetrad cell.

The cells of the Tetrad separate and prepare for a final division.

The final Division produces a small cell which is located in the cytoplasm of a larger cell. A thick cell wall develops around the large cell.

The Mature Pollen Grain (Microgametophyte) has a thick multilayered wall, a large Tube Cell and a small Generative Cell. The Generative Cell floats in the cytoplasm of the Tube Cell.

The wall has several weak spots called Pores. After pollen has reached a receptive Stigma, the Tube Cell produces a Pollen Tube which ruptures one of the pores.

The Generative Cell undergoes another division to produce two NON-Flagellated Sperm Cells which migrate with the Tube Cell nucleus to the tip of the Pollen Tube

Pollen arrives on the Stigma & Germinates.

The Pollen Tube grows between the Cell Walls of the Transmitting Tissue in the Style.

Pollen Tubes eventually reach the Micropyle of Ovules in the Ovary.