Module: | Pollination & Outbreeding Devices
Q44: Consider the following statements regarding the post-fertilization degradation of embryo sac components:
1. Upon the targeted entry of the pollen tube into the embryo sac, one of the two synergids is rapidly destroyed or degenerates.
2. The three antipodal cells undergo massive mitotic proliferation immediately following double fertilization to assist the endosperm.
3. The second, undisturbed synergid typically degenerates shortly after the completion of syngamy and triple fusion.
Which of the above statements is/are correct?
2. The three antipodal cells undergo massive mitotic proliferation immediately following double fertilization to assist the endosperm.
3. The second, undisturbed synergid typically degenerates shortly after the completion of syngamy and triple fusion.
Which of the above statements is/are correct?
✅ Correct Answer: B
The correct option is B. Statements 1 and 3 are correct, whereas Statement 2 is entirely incorrect.
The mature 7-celled, 8-nucleate embryo sac undergoes rapid structural demolition following double fertilization, leaving only the newly formed zygote and the primary endosperm cell (PEC). Causally, the pollen tube does not enter the embryo sac randomly; it is guided by the filiform apparatus into one specific synergid.
The physical entry and discharge of the male gametes cause the immediate destruction or degeneration of that penetrated synergid.
The second synergid, having fulfilled its localized chemical attraction role, also degenerates shortly after fertilization is complete.
Statement 2 is a physiological distractor: the antipodal cells at the chalazal end, whose precise function is often vestigial or minorly nutritive, do not proliferate.
They degenerate and disappear completely shortly before or immediately after fertilization.
The mature 7-celled, 8-nucleate embryo sac undergoes rapid structural demolition following double fertilization, leaving only the newly formed zygote and the primary endosperm cell (PEC). Causally, the pollen tube does not enter the embryo sac randomly; it is guided by the filiform apparatus into one specific synergid.
The physical entry and discharge of the male gametes cause the immediate destruction or degeneration of that penetrated synergid.
The second synergid, having fulfilled its localized chemical attraction role, also degenerates shortly after fertilization is complete.
Statement 2 is a physiological distractor: the antipodal cells at the chalazal end, whose precise function is often vestigial or minorly nutritive, do not proliferate.
They degenerate and disappear completely shortly before or immediately after fertilization.