Module: | Pollination & Outbreeding Devices
Q39: Consider the following statements regarding the mechanics of cleavage polyembryony:
1. Cleavage polyembryony involves the physical splitting or proliferation of the proembryo into multiple, independent embryos.
2. While it is a standard and common feature in gymnosperms like Pinus, it is also natively reported in certain angiosperms such as orchids.
3. Adventive embryony is simply a sub-type of cleavage polyembryony where the zygote splits into dozens of fragments.
Which of the above statements is/are correct?
2. While it is a standard and common feature in gymnosperms like Pinus, it is also natively reported in certain angiosperms such as orchids.
3. Adventive embryony is simply a sub-type of cleavage polyembryony where the zygote splits into dozens of fragments.
Which of the above statements is/are correct?
✅ Correct Answer: A
The correct option is A. Statements 1 and 2 are correct, but Statement 3 is incorrect.
Polyembryony has multiple structural origins.
Cleavage polyembryony is the most direct form of true polyembryony, where a single fertilized zygote divides to form a proembryo, which then undergoes chaotic or programmed splitting to yield multiple embryonic masses, each capable of forming a plant.
Causally, because they arise from the same zygote, these embryos are genetically identical to each other (like identical human twins). This mechanism is highly characteristic of gymnosperms but is occasionally seen in angiosperm families like Orchidaceae.
Statement 3 represents a fundamental classification error.
Adventive embryony is entirely distinct from cleavage polyembryony; adventive embryos do not arise from the zygote at all, but rather from the maternal diploid tissues (nucellus or integuments) pushing their way into the embryo sac.
Polyembryony has multiple structural origins.
Cleavage polyembryony is the most direct form of true polyembryony, where a single fertilized zygote divides to form a proembryo, which then undergoes chaotic or programmed splitting to yield multiple embryonic masses, each capable of forming a plant.
Causally, because they arise from the same zygote, these embryos are genetically identical to each other (like identical human twins). This mechanism is highly characteristic of gymnosperms but is occasionally seen in angiosperm families like Orchidaceae.
Statement 3 represents a fundamental classification error.
Adventive embryony is entirely distinct from cleavage polyembryony; adventive embryos do not arise from the zygote at all, but rather from the maternal diploid tissues (nucellus or integuments) pushing their way into the embryo sac.