Difference Between Agamospermy and Apomixis

The key difference between agamospermy and apomixis is their occurrence. Agamospermy mainly occurs in gymnosperms, while apomixis mainly occurs in angiosperms.

Plants reproduce asexually as well as sexually. Agamospermy and apomixis are two asexual modes of reproduction taking place in higher plants. They replace the process of formation of gametes. Moreover, during these processes, the fertilization event also does not take place in the development of the offspring.

CONTENTS

1. Overview and Key Difference
2. What is Agamospermy
3. What is Apomixis
4. Similarities Between Agamospermy and Apomixis
5. Side by Side Comparison – Agamospermy vs Apomixis in Tabular Form
6. Summary

What is Agamospermy?

Agamospermy is the process of formation of the embryo through asexual reproduction methods. Therefore, there is no formation of gametes in this process. Moreover, the act of fertilization is also absent in plants undergoing agamospermy. Agamospermy mainly takes place in gymnosperms to produce clonal seeds.

There are three types of agamospermy taking place in plants. The first is the recurrent agamospermy. During this process, the formation of a diploid embryonic sac takes place from diploid nucellar cells. It is also known as apospory. Additionally, the formation of the embryonic sac also takes place from the megaspore mother cells in a process called diplospory. The development of this embryo takes place parthenogenetically; thus, there is no fertilization.

Secondly, non-recurrent agamospermy takes place when the megaspore mother cell divides to form a haploid embryo sac through meiosis. However, fertilization does not take place and results in sterile embryos. Thirdly, adventive embryony is the process of embryo development that takes place via the nucellar cells or the integuments of the ovule. A fertilized egg is not required for embryonic development.

What is Apomixis?

Apomixis is also known as agamospermy. However, the difference is that the apomixis occurs in a wide variety of plant groups in contrast to agamospermy. Here, this apomixis refers to the asexual reproduction method, which does not involve any gametes. Thus, the offspring are genetically identical to their parents.

Apomixis readily takes place in flowering plants or angiosperms. In contrast to agamospermy, apomixis has four types. The first three types are similar to agamospermy. They are recurrent apomixis, non-recurrent apomixis, and adventive embryony. However, the fourth type, which is vegetative apomixis, is only present in apomixis and refers to the replacement of flowers by bulbils.

What are the Similarities Between Agamospermy and Apomixis?

• Both are asexual methods of reproduction.
• They do not involve in the production of gametes.
• But, both produce genetically identical offspring to their parents.

What is the Difference Between Agamospermy and Apomixis?

There is a minute difference between agamospermy and apomixis. Agamospermy takes place in gymnosperms while apomixis mostly takes place in angiosperms. Furthermore, vegetative asexual reproduction takes place in apomixis, but not in agamospermy. So, this is also a difference between agamospermy and apomixis.

Summary – Agamospermy vs Apomixis

Agamospermy and apomixis are asexual reproduction methods in higher plants. Agamospermy occurs predominantly in gymnosperms and results in the production of clonal seeds. In contrast, apomixis occurs predominantly in angiosperms or flowering plants. They replace the flower structure with vegetative parts such as the bulbils. So, this serves as the key difference between agamospermy and apomixis. However, both are adaptations shown by plants for survival and for the maintenance of their genetic composition.

Reference:

1. “Asexual R eproduction in Agamospermy.” Biology Discussion, 27 Aug. 2015, Available here.
2. “Parthenocarpy&Apomixis: Concepts, Similarities, Differences, Examples.” Toppr, 20 Sept. 2018, Available here.

Image Courtesy:

1. “1135399” (CC0) via Pexels
2. “Poa bulbosa, vegetative apomixis” By Nadiatalent – Own work (CC BY-SA 3.0) via Commons Wikimedia