Practicing Success
What is the term used to describe the formation of the embryo sac from a single megaspore? |
Polymeric development Monosporic development Bisporic development Multisporic development |
Monosporic development |
The answer is b) Monosporic development. Monosporic development is the process of forming an embryo sac from a single megaspore. This is the most common type of embryo sac development in flowering plants. In monosporic development, the megaspore mother cell undergoes meiosis and forms four megaspores. However, only one of these megaspores is functional and develops into the embryo sac. The other three megaspores degenerate. The functional megaspore undergoes three rounds of mitosis to form the mature embryo sac. The mature embryo sac contains seven cells and eight nuclei. The egg cell, which is fertilized by a sperm cell to produce a zygote, is located in the chalazal end of the embryo sac. The cells of the embryo sac are:
Polymeric development, bisporic development, and multisporic development are all types of embryo sac development in which more than one megaspore is involved in the formation of the embryo sac. |