Скачать или смотреть Apomixixs and polyembryony

Apomixis and polyembryony are two different reproductive phenomena found in plants. Here’s a brief explanation of each:

Apomixis

Apomixis is a form of asexual reproduction that mimics sexual reproduction but does not involve fertilization. It allows plants to produce seeds without the genetic contribution from a male gamete (sperm). The seeds produced through apomixis are genetically identical to the parent plant. There are two main types of apomixis:

Gametophytic Apomixis: In this type, the embryo arises from an unfertilized egg cell that is part of the gametophyte.

Sporophytic Apomixis: Here, the embryo is formed directly from somatic cells of the ovule, bypassing the gametophyte stage.

Polyembryony

Polyembryony refers to the phenomenon where two or more embryos develop from a single fertilized egg or within a single seed. This can result in multiple seedlings emerging from one seed. Polyembryony can occur due to several reasons:

Cleavage Polyembryony: This happens when the zygote or early embryo splits into several embryos.

Adventive Embryony: Here, additional embryos develop from somatic or nucellar cells surrounding the embryo sac.

Multiple Fertilizations: In some cases, more than one egg within the ovule gets fertilized, leading to multiple embryos.

Both apomixis and polyembryony are significant for plant breeding and agriculture. Apomixis is beneficial for producing uniform and stable plant varieties, while polyembryony can contribute to hybrid vigor and increased seedling production.