Question

What is a megagametophyte?

Answer 1

Gametophyte is one of the reproductive phases in plants like mosses and bryophytes. Megagametophyte is the female gamete which is also known as embryo sac. In heterosporous plants, the megagametophyte develops from the megaspores. The megagametophyte acts as an embryo sac in Angiosperms.

Complete answer:
Reproduction is an important aspect in living things. It is a process by which genetically similar offspring are produced by parent plants. Reproduction can be of sexual or asexual means. Sexual reproduction takes place when there is an involvement of male and female gametes, whereas, asexual reproduction has no involvement of either gametes.
In some plants and algae, there are two reproductive phase, that is a sexual and an asexual phase. This striking phenomenon is known as alternation of generations. The sexual phase is known as gametophyte and the asexual phase is known as sporophyte.
Megagametogenesis is the process in which the megagametophytes are matured and developed. A megagametophyte gives rise to the female gametes known as eggs. These egg cells are involved in the process of pollination and fertilization.
Additional information: The male gamete is known as the microgametophyte. Microsporangium consists of microsporocytes. This develops into a microgametophyte consisting of the sperms. Once pollination occurs, the next generation starts, which is known as sporophyte.

Note:
Megasporangium is an immature ovule. Megasporocytes are present inside the ovule. They develop into megaspores. The megaspore gives rise to the megagametocyte which is the female gamete. These megagametocyte develop into a mature ovule. In some plants, they perform the function of an embryo sac.