Question

Development of embryo from a cell of embryo sac other than egg is an example of
A. Apospory
B. Apogamy
C. Adventive embryony
D. Parthenogenesis

Answer 1

Hint: The embryonic development when occurring without fertilization from cells that are not egg cells. This process requires embryo development, such as integuments and nucellus, from the diploid sporophytic cells of the ovule. It may also contribute to more than one embryo being developed within a single seed.

Complete Answer:
To understand this question we need to develop an idea about all the options in
the question.
1. Apospory is gametophyte development from the sporophyte cells without spore formation. There is the development of 2n gametophytes, without meiosis from vegetative/non-reproductive cells of the sporophyte.
2. Apogamy is the development of sporophyte from the cell of embryo sac (gametophyte), other than oosphere without the gamete fusion. There is development of 1n sporophyte.
3. In case of adventive embryogeny, there occurs formation of extra embryos due to sporophytic budding. Now, one or many sporophytic cells, integuments or nuclei might undergo the process of embryogeny stages in order to develop into a mature embryo.
4. Parthenogenesis is the process of formation of an embryo from unfertilized egg or female gamete. Hence, the development of an embryo from a cell of embryo sac other than the egg is an example of Adventive embryogeny.

So, the correct answer is option (C) Adventive embryogeny.

Note: Adventive polyembryony is also an example of agamospermy which is is a type of asexual reproduction where plant propagation occurs by means of apomictic seeds (or asexual seeds). Adventive embryos may develop from nucellus or chalaza (apospory) somatic cells and may occur along with a typical zygotic embryo. One seed, as is often the case with citrus plants, may contain many embryos. Alternatively, the unreduced egg cell may develop an embryo (diplospory).