Question

In sporophytic polyembryony, the additional embryos develop from
A.Nucellus
B.Integument
C.First formed embryo
D.All the above

Answer 1

Polyembryony is the phenomenon where there are multiple embryos within a given embryonic sac of a plant, where the additional embryo can develop and differentiate from various zygotic and maternal tissue. Sporophytic polyembryony is when multiple embryos are formed during asexual reproduction from maternal cells. In such a case the additional embryos are developed from either the zygote/embryo or from other sporophytic cells such as the nucellus and integument.

Complete answer: Polyembryony is a phenomenon where more than two embryos develop from a single fertilized cell. This is a common characteristic seen in many organisms including vertebrates, invertebrates, and even in plants.
In plants, this specifically refers to the development of multiple embryos within the embryo sac of the ovary. There are many ways in which polyembryony is activated in plants, such as, through zygotes and synergid cells formed from sexual reproduction, through nucellus and integuments in the case of sporophytic reproduction, and through synergids and antipodal cell in gametophytic reproduction.
Sporophytic polyembryony refers to the formation of the additional embryo via the sporophyte cells which are the nucleus and the integument. The embryos which arise from sporophyte cells are called adventive embryos and the polyembryony is called adventive polyembryony.
The additional embryo can also be formed by the zygote/proembryo formed during spore generation which can divide during embryogenesis.
Therefore, the correct answer is option D. All the above

Note: Polyembryony is the phenomenon where multiple embryos develop from a single fertilized egg. Twins are examples of polyembryony. In the case of plants, it refers to multiple embryos being present within the embryonic sac.
In plants, the additional embryo can be from other zygotic tissue and maternal cells and need not necessarily be from the proembryo. Other cells that can form the additional embryos are synergids, antipodal cells, nucellus, and integument.
The nucellus is the central part of the ovule from which the embryo sac develops, and the integument is the protective layer surrounding the ovule. Seed production via these cells is considered a form of apomixis.