[ meg-uh-spawr-uh-jen-uh-sis, -spohr- ]


, Botany.
  1. the formation and development of megaspores.


/ mĕg′ə-spôr′ə-jĕnĭ-sĭs /

  1. The formation of megaspores inside the ovules of seed plants. A diploid cell in the ovule, called a megasporocyte or a megaspore mother cell, undergoes meiosis and gives rise to four haploid megaspores. In most plants, only one of the megaspores then goes on to develop into a megagametophyte within the ovule, while the other three disintegrate. In the ovules of angiosperms, megasporogenesis takes place within a structure called a nucellus, and it is the megaspore farthest from the micropyle of the ovary that survives.


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More About Megasporogenesis

What does megasporogenesis mean?

Megasporogenesis is the process by which megaspores are formed in the ovule of a seed plant. This megaspore goes on to become part of the ovule (the “egg”) in the plant’s reproduction.

Spores are reproductive parts of an organism, especially those of plants and fungi.

Megasporogenesis is similar to microsporogenesis, which produces much smaller pollen grains. The combination of pollen with an ovule results in reproduction.

Why is megasporogenesis important?

Megasporogenesis is an important part of how plants reproduce. How it works is all right there in the word: mega- means “big,” sporo refers to spores, and genesis refers to creation or generation. So, megasporogenesis is the generation of big spores called megaspores.

A flower has two distinct bits for reproduction: its pollen sacs and its gynoecium. These refer broadly to the “male” and “female” parts of the flower. The gynoecium is where megasporogenesis takes place. A cell called the megasporocyte splits into four parts through meiosis, and these four parts become four megaspores. Generally, just one of these megaspores continues to live, while the others break down. The surviving megaspore becomes the embryo sac of the plant, which has the egg cell inside it. This megaspore will eventually be fertilized by pollen from the same or another plant.

This pollen is created by the process of microsporogenesis. Understanding microsporogenesis and megasporogenesis is crucial to understanding plant reproduction.

Did you know ... ?

Megasporogenesis and microsporogenesis sound similar, and they’re both parts of plant reproduction, but they involve very different processes. To remember the difference, think about it this way: megasporogenesis produces the big (mega) part (the ovule, or egg), and microsporogenesis produces the small (micro) parts, the tiny pollen grains.

What are real-life examples of megasporogenesis?

Megasporogenesis is typically discussed in the contexts of botany and biology.



What other words are related to megasporogenesis?

Quiz yourself!

True or False?

The megaspore produced in the process of megasporogenesis is roughly analogous to an egg.