Question

In the case of polyembryony, if an embryo develops from the synergid and another from the nucellus, then the synergid embryo is (I) and nucellar embryo is (II)

	(I)	(II)
(i)	triploid	haploid
(ii)	diploid	haploid
(iii)	haploid	diploid
(iv)	diploid	triploid

• A. (i)
• B. (ii)
• C. (iii)
• D. (iv)

Answer 1

Answer: (C)

Apogamy- It is a type of polyembryony in which embryos may be produced sometimes due to the fertilization of cells of the embryo sac other than the egg. The most common source is synergid. Production of embryos from antipodal cells are rare.
Adventive polyembryony- It is a type of polyembryony, where embryos originate from diploid cells of ovule lying outside the embryo sac and either belong to integuments or nucellus. The embryos are rich in protoplasm and divide actively to produce small masses of cells that protrude into the embryo sac and eventually form true embryos and are distinguishable from the ones developed from egg cells due to lack of suspensor.
Synergid cells are the two nuclei present in the embryo sac around the egg, they are haploid, and they perform the function of directing the pollen tube towards the female gametophyte, whereas nucellus is the diploid cell present in the embryo of the cell and one of its cells differentiates and forms the ovule.
Synergid is the outcome of meiosis and is a part of the gametophyte, so it is haploid. The nucellus is diploid tissue because it is a part of the sporophyte.