APOMIXIS IN FLOWERING PLANTS
Reproduction in plants is of two types:
- Sexual or Amphimixis
- Asexual or Apomixis
Angiosperms have a Diplontic life cycle. The main part of the lifecycle is Sporophyte & the Gametophyte is reduced.
Apomixis mimics sexual reproduction but produces seeds without fertilization. Seen in some species of Family Asteraceae & Grasses.
It is of 3 types:
- Apogamy: Formation of sporophyte/embryo from any cell of the gametophyte/embryo sac without fertilization. Cells of the embryo sac i.e., antipodal cells or the synergids. The embryo formed is haploid.
- Apospory: Formation of gametophyte i.e., the embryo sac from any cell of the sporophyte without meiosis. Cells of the sporophyte are cells of nucellus & integuments. The embryo sac formed has diploid cells. The egg is also diploid. Diploid egg either undergo fertilization or undergoes Parthenogenesis.
- Parthenogenesis: Formation of the embryo from the egg without fertilization.