Module: | Pre-fertilization: Micro/Megasporogenesis
Q31: Consider the following statements regarding the occurrence of polyembryony:
1. Polyembryony is strictly defined as the occurrence of more than one embryo within a single mature seed.
2. In varieties of Citrus and Mango, diploid cells of the nucellus surrounding the embryo sac actively divide, protrude into the sac, and develop into multiple embryos.
3. These adventive embryos, being derived from the nucellus, are haploid and genetically distinct from the parent plant.
Which of the above statements is/are correct?
2. In varieties of Citrus and Mango, diploid cells of the nucellus surrounding the embryo sac actively divide, protrude into the sac, and develop into multiple embryos.
3. These adventive embryos, being derived from the nucellus, are haploid and genetically distinct from the parent plant.
Which of the above statements is/are correct?
✅ Correct Answer: A
The correct option is A. Statements 1 and 2 are correct, while Statement 3 is incorrect.
Polyembryony is a condition where a seed contains multiple embryos.
While it can occur via the splitting of a single zygote, a very common and highly tested mechanism in angiosperms is adventive embryony, famously seen in Citrus (oranges, lemons) and Mangoes.
In these plants, some of the maternal sporophytic cells of the nucellus, which are adjacent to the embryo sac, spontaneously begin to undergo mitotic division.
These cell masses push into the embryo sac and mature into embryos alongside the normal zygotic embryo.
Statement 3 is incorrect because the nucellus is maternal, somatic tissue; therefore, it is diploid (2n). Consequently, these adventive embryos are diploid genetic clones of the mother plant, providing a natural method for clonal propagation in horticulture.
Polyembryony is a condition where a seed contains multiple embryos.
While it can occur via the splitting of a single zygote, a very common and highly tested mechanism in angiosperms is adventive embryony, famously seen in Citrus (oranges, lemons) and Mangoes.
In these plants, some of the maternal sporophytic cells of the nucellus, which are adjacent to the embryo sac, spontaneously begin to undergo mitotic division.
These cell masses push into the embryo sac and mature into embryos alongside the normal zygotic embryo.
Statement 3 is incorrect because the nucellus is maternal, somatic tissue; therefore, it is diploid (2n). Consequently, these adventive embryos are diploid genetic clones of the mother plant, providing a natural method for clonal propagation in horticulture.