Module: | Pollination & Outbreeding Devices
Q45: Consider the following statements regarding the comparative origin and ploidy of the endosperm:
1. In angiosperms, the endosperm is a post-fertilization tissue formed specifically by the process of triple fusion, making it typically triploid.
2. In gymnosperms, the endosperm is a pre-fertilization tissue representing the vegetative part of the female gametophyte, making it strictly haploid.
3. Despite their different ploidy levels, the endosperms of both angiosperms and gymnosperms develop directly from the Primary Endosperm Nucleus (PEN).
Which of the above statements is/are correct?
2. In gymnosperms, the endosperm is a pre-fertilization tissue representing the vegetative part of the female gametophyte, making it strictly haploid.
3. Despite their different ploidy levels, the endosperms of both angiosperms and gymnosperms develop directly from the Primary Endosperm Nucleus (PEN).
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.
The concept of the "endosperm" spans across both gymnosperms and angiosperms, but the term describes two fundamentally different evolutionary structures.
In flowering plants (angiosperms), it is a novel, post-fertilization tissue created by the fusion of one male gamete with two polar nuclei (triple fusion), resulting in a triploid (3n) status.
In naked-seed plants (gymnosperms like Pinus), double fertilization does not occur.
What is functionally termed the "endosperm" is actually the massive, multicellular female gametophyte tissue that develops long before fertilization takes place to house the archegonia.
Because it develops from a haploid megaspore without any gametic fusion, it is strictly haploid (n). Statement 3 fails because gymnosperms never form a Primary Endosperm Nucleus (PEN); the PEN is an exclusive byproduct of angiosperm triple fusion.
The concept of the "endosperm" spans across both gymnosperms and angiosperms, but the term describes two fundamentally different evolutionary structures.
In flowering plants (angiosperms), it is a novel, post-fertilization tissue created by the fusion of one male gamete with two polar nuclei (triple fusion), resulting in a triploid (3n) status.
In naked-seed plants (gymnosperms like Pinus), double fertilization does not occur.
What is functionally termed the "endosperm" is actually the massive, multicellular female gametophyte tissue that develops long before fertilization takes place to house the archegonia.
Because it develops from a haploid megaspore without any gametic fusion, it is strictly haploid (n). Statement 3 fails because gymnosperms never form a Primary Endosperm Nucleus (PEN); the PEN is an exclusive byproduct of angiosperm triple fusion.