Functional Megastore in an Angiosperm

An angiosperm is a type of flowering plant that reproduces by producing flowers. One important structure that develops in angiosperms is the functional megastore. The functional megastore plays a crucial role in the reproductive process of angiosperms, specifically in the development of seeds and fruits.

What is a Functional Megastore?

The functional megastore is a specialized tissue within the ovary of a flower. It is formed from the fusion of several megaspores within the ovule. The megaspores undergo mitotic divisions to form a large, multicellular structure known as the functional megastore. It is responsible for the formation of the embryo sac, which contains the female gametophyte, as well as the surrounding tissues that support the development of seeds and fruits.

Formation of the Functional Megastore

1. Megaspore Mother Cell: The functional megastore begins its development from a megaspore mother cell, which is located within the ovule of the flower.
2. Megaspore Formation: The megaspore mother cell undergoes meiosis to produce four megaspores.
3. Megaspore Degeneration: In most angiosperms, three of the four megaspores degenerate, leaving only one functional megaspore.
4. Mitotic Divisions: The functional megaspore undergoes several rounds of mitotic divisions to form a large, multicellular structure.
5. Formation of Embryo Sac: Within the functional megaspore, the cells differentiate to form the embryo sac, which contains the female gametophyte.
6. Supporting Tissues: The functional megastore also gives rise to the surrounding tissues, such as the integuments, which protect the developing embryo sac, and the nucellus, which provides nutrients to the developing seed.

Role of the Functional Megastore

The functional megastore plays a crucial role in the reproductive process of angiosperms. It is responsible for several key functions, including:

1. Embryo Sac Formation: The functional megastore gives rise to the embryo sac, which contains the female gametophyte. This is where fertilization takes place.
2. Seed Development: The functional megastore provides the necessary support and nutrients for the development of seeds.
3. Fruit Formation: After fertilization, the functional megastore undergoes further development to form the fruit, which protects the developing seeds and aids in their dispersal.
4. Seed Dispersal: The functional megastore plays a role in the dispersal of seeds by developing structures such as wings, hooks, or fleshy tissues that aid in wind, animal, or water dispersal.

In conclusion, the functional megastore in an angiosperm develops from a megaspore within the ovule. It plays a crucial role in the development of seeds and fruits, including the formation of the embryo sac, support of seed development, fruit formation, and seed dispersal.