Main content
Course: Class 12 Biology (India) > Unit 2
Lesson 4: Post-fertilization events, apomixis, and polyembryonyApomixis and polyembryony
Overview of apomixis and polyembryony
Key terms
| Term | Meaning |
|---|---|
| apomixis | a form of asexual reproduction that results in seed formation without fertilization |
| parthenocarpy | formation of fruits without fertilization |
| polyembryony | occurrence of multiple embryos within an ovule |
What is apomixis?
Have you ever heard about certain insects and reptiles that occasionally reproduce without fertilization of gametes? Something similar can happen in flowering plants, wherein seeds are produced in the absence of fertilization. This process is known as apomixis, and the seeds produced by it are called apomictic seeds.
The key point to note here is that apomixis is a type of asexual reproduction that imitates sexual reproduction (since it results in seed formation).
How does this happen?
In some cases, meiosis fails to occur, and so a diploid egg cell forms in the embryo sac and develops directly into the embryo.
In other species, including Citrus and certain mango varieties, cells from the nucellus begin to divide, invade the embryo sac, and develop into embryos. This type of apomixis results in formation of multiple embryos within a single ovule or seed, a phenomenon known as polyembryony. The image below depicts a lemon slice with multiple seeds visible.