1, apomixis in plants: vegetative reproduction can replace sexual reproduction, for example, aerial roots often form on garlic racemes, which can replace seeds;
2. Apomixis: Apomixis that can produce seeds. Including three categories:
(1) Haploid gametophyte apomixis refers to the reproductive mode in which male and female gametes produce haploid embryos without normal fertilization, which is called parthenogenesis for short. It can be divided into parthenogenesis (gynogenesis) and parthenogenesis (androgenesis).
Parthenogenesis: the phenomenon that an egg cell develops directly into an individual without fertilization, but its polar cell still needs fertilization to develop into endosperm, so pollination is still necessary.
Parthenogenesis: After sperm enters the egg, the egg nucleus degenerates and disintegrates immediately, and only embryos with paternal chromosomes develop in the cytoplasm of the egg. At present, using pollen to induce haploid plants is a way to artificially create parthenogenesis.
(2) The diploid gametophyte is apomixis. Apomixis develops from diploid gametophyte. Because the nuclei in embryo sac are diploid and have not undergone meiosis, the process of their development into sporophyte is also called non-meiotic parthenogenesis.
(3) Exotic embryos. The phenomenon that an embryo develops directly from the dentate cell of nucellus or integument without gamete stage. It belongs to a simple way of not merging knots. This method is often fused with gametes in citrus. Only one embryo in many embryos is fertilized normally, and the rest embryos are adventitious embryos with nucellar cells entering the embryo sac. It exists in citrus, sorghum and other plants.