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Difference Between Apomix and Polyembryony

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Introduction on Apomix and Polyembryony

Apomixis and polyembryony are reproductive strategies in plants. Apomixis is asexual reproduction where seeds form without fertilization, yielding offspring that are genetically identical to the parent. In contrast, polyembryony occurs when a single fertilized ovule gives rise to multiple embryos, which can be either genetically identical or diverse depending on the developmental process.


Key Difference Between Apomix and Polyembryony

Aspect

Apomixis

Polyembryony

Definition

Asexual reproduction where seeds form without fertilization.

Formation of multiple embryos from a single fertilized ovule.

Reproductive Process

Bypasses meiosis and fertilization, producing clonal offspring.

Involves fertilization; one zygote or additional embryogenic cells give rise to multiple embryos.

Genetic Variation

Offspring are genetically identical to the parent.

Offspring may be genetically identical if from a single zygote, or show variation if somatic embryos form.

Fertilization Requirement

Does not require fertilization.

Requires fertilization of the ovule.

Outcome

Produces seeds that are clones of the mother plant.

Results in a seed containing more than one embryo, potentially yielding multiple seedlings.

Developmental Mechanism

Often involves mechanisms such as gametophytic or sporophytic apomixis to bypass sexual reproduction.

May occur via cleavage of the zygote or by the formation of additional somatic embryos from surrounding cells.

Occurrence

Common in some grass species, dandelions, and certain citrus plants.

Observed in species like mango, citrus, and certain conifers.

Ecological Significance

Ensures rapid colonization and maintenance of successful genotypes in stable environments.

Can increase the chances of survival by producing more than one embryo, potentially adapting to variable conditions.

Developmental Timing

Develops seeds without the genetic recombination typical of sexual reproduction.

Multiple embryos develop concurrently within a single seed, sometimes with competition for resources.

Applications

Useful in agriculture to fix desirable traits in crops through clonal seed production.

Can be exploited in breeding programs to select for multiple traits or to study embryo development dynamics.


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FAQs on Difference Between Apomix and Polyembryony

1. What is the difference between apomixis and polyembryony with example?

Apomixis is an asexual reproductive process where seeds form without fertilization, producing offspring that are genetic clones of the parent (e.g., dandelions). In contrast, polyembryony involves the formation of multiple embryos from a single fertilized ovule, as seen in mango and certain citrus species.

2. What is the difference between apomixis, polyembryony, and parthenocarpy?

Apomixis produces seeds asexually without fertilization, while polyembryony generates more than one embryo from one fertilized ovule. Parthenocarpy, on the other hand, is the development of fruit without fertilization, typically resulting in seedless fruits.

3. What are two examples of polyembryony?

Mango and certain citrus fruits (e.g., oranges) are common examples where polyembryony occurs, resulting in multiple seedlings per seed.

4. What are the 4 types of apomixis?

The four types can be classified as:

  • Autonomous apomixis: where embryo development is independent of fertilization.

  • Pseudogamous apomixis: where fertilization is required for endosperm development but not for the embryo.

  • Gametophytic apospory: where the embryo sac forms from somatic nucellar cells, bypassing meiosis.

  • Gametophytic diplospory: where the embryo sac develops from the megaspore mother cell without reduction division.

5. Is mango an example of apomixis?

No, mango is generally known for exhibiting polyembryony, where multiple embryos form within a single seed.

6. What is apomixis with example?

Apomixis is asexual seed formation without fertilization, resulting in clones of the parent plant; for example, many dandelion species reproduce through apomixis.

7. What is the difference between parthenocarpy and polyembryony?

Parthenocarpy is the formation of fruit without fertilization, leading to seedless fruits, while polyembryony is the development of multiple embryos from one fertilized ovule, resulting in several seedlings from a single seed.

8. What is the meaning of parthenogenesis?

Parthenogenesis is a form of asexual reproduction where an egg develops into an organism without fertilization, common in some invertebrates, reptiles, and plants (as seen in parthenocarpic fruit development).

9. Is jackfruit a polyembryony?

No, jackfruit does not typically exhibit polyembryony; it generally produces a single embryo per seed.

10. Is tomato polyembryony?

Tomatoes are not known to be polyembryonic; they normally develop one embryo per fertilized ovule, following standard sexual reproduction.