Prothallus Formation in Pteridophytes
In pteridophytes, the spores germinate to form a structure known as a prothallus. The prothallus is a small, flat, heart-shaped structure that serves as the gametophyte generation in the life cycle of ferns and other related plants.

Germination of Spores
When a spore lands on a suitable substrate, it germinates to form a prothallus. The spore contains a single-celled structure called a prothallial cell that divides and grows to form the prothallus.

Structure of Prothallus
The prothallus is a haploid structure, meaning it contains only one set of chromosomes. It is typically green in color due to the presence of chlorophyll, allowing it to photosynthesize and produce its own food.

Function of Prothallus
The prothallus is responsible for producing both male and female gametes. It houses the male reproductive structures called antheridia, which produce sperm cells, and the female reproductive structures called archegonia, which produce egg cells.

Fertilization and Sporophyte Development
Once fertilization occurs between the sperm and egg cells produced on the prothallus, a zygote is formed. This zygote develops into a new sporophyte, which is the diploid phase of the fern life cycle. The sporophyte eventually grows into the familiar fern plant that we recognize.
In conclusion, the spores in pteridophytes germinate to form a prothallus, which serves as the gametophyte generation in the life cycle of these plants. The prothallus plays a crucial role in producing gametes and facilitating fertilization, leading to the development of the sporophyte phase.