Apomixis in Plants
Apomixis in plants is the formation of seeds without the reproductive process. Therefore, the reproduction of plants by such seeds is asexual, or vegetative. This type of apomixis is of the greatest importance, in which miosis is completely excluded. Seed is formed directly from a diploid cell, which can be an unreduced megaspore of the mother cell or any cell from the mother germinal tissue. As a result of apomixis, heterozygous cross-pollinating plants genetically accurately reproduce themselves in seeds.
Apomixis is characterized as reproduction, not associated with the fusion of male and female gametes, but with the help of seeds. Apomixis can be constant – hereditary or accidental – non-hereditary, as well as induced, or stimulative, i.e., associated with pollination and exposure to the pollen tube, and autonomous, independent of pollination.
Although apomixis is widespread in the plant world, it is not the usual way of asexual reproduction. Apomixis is used in the reproduction of meadow grass, citrus and mango. But these species are only partially apomictic. Their seeds are formed both as a result of the sexual and apomictic process.
The apomixis phenomenon in angiosperms is very diverse and complex, therefore it is not surprising that until very recently there has been no consensus among researchers on the classification and terminology of its forms.