The primary difference is that the filiform apparatus is a structural component of the synergid cells, aiding in pollen tube guidance, while the egg apparatus comprises the egg cell and synergids, responsible for fertilization.
Here's a more detailed breakdown:
Egg Apparatus
The egg apparatus is a cluster of cells found at the micropylar end (the end with an opening) of the embryo sac in flowering plants (angiosperms). It's crucial for fertilization.
- Composition: The egg apparatus consists of the egg cell and usually two synergid cells.
- Function: The egg cell is the female gamete that fuses with the sperm nucleus from the pollen tube to form the zygote. The synergids play a vital role in attracting the pollen tube and facilitating sperm delivery.
Filiform Apparatus
The filiform apparatus is a prominent feature of the synergid cells within the egg apparatus.
- Composition: It is characterized by finger-like projections, or invaginations, of the cell wall extending into the cytoplasm of the synergids.
- Function: The filiform apparatus guides the pollen tube to the synergid cell. After the pollen tube enters the synergid, it ruptures and releases the sperm cells, one of which fertilizes the egg cell. The filiform apparatus is believed to be involved in the production and secretion of chemoattractants that attract the pollen tube.
Summary Table
| Feature | Egg Apparatus | Filiform Apparatus |
|---|---|---|
| Location | Micropylar end of the embryo sac | Synergid cells (within the egg apparatus) |
| Cellular Makeup | Egg cell and synergids | Modified cell wall (invaginations) of synergids |
| Primary Function | Fertilization; zygote formation | Pollen tube guidance and sperm delivery to egg cell |
