Unlock the secrets of plant reproduction with our in-depth exploration of apomixis and polyembryony. Learn more now!
Apomixis and Polyembryony
Apomixis is the alternative method of seed production. It is the process of seed production without fertilization of egg, This process bypasses both meiosis and syngamy. Hence it is an asexual method.
Apomixis
This is very much demand for seed development in Hybrid plants. Mainly citrus and opuntia show apomictic seeds. Apomixis is mainly found in families like Asteraceae and Poaceae.
Methods in Apomixis
There are different methods followed for developing apomictic seeds like,
- Sporophytic budding: Here, the vegetative diploid cells of ovule integument or nucellus develop into embryo directly.
- Dilospory: In this method the diploid Megaspore mother cell directly develops into a diploid embryo sac.
- Apospory: Here, the diploid nucellar cell develops into diploid embryo sac.
Both Diplospory and Apospory are called Recurrent Apomixis. In these cases, the egg as well as synergids and antipodals are also diploid. If a diploid egg directly develops to give embryo, the process of apomixis is called as parthenogenesis. Similarly, the embryo formation from synergid or antipodal cell is called as apogamy.
Polyembryony
The single ovule has developed many embryos. Polyembryony is due to apomixis. It is more common in citrus. Adventitive polyembryony is seen in citrus and mango.
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