Module: | Pre-fertilization: Micro/Megasporogenesis
Q3: Consider the following statements regarding the shedding stages of pollen grains:
1. In over 60 percent of angiosperms, pollen grains are shed at the 2-celled stage.
2. The vegetative cell is small, spindle-shaped, and floats in the cytoplasm of the generative cell.
3. In species that shed at the 3-celled stage, the generative cell divides mitotically to form two male gametes before shedding.
Which of the above statements is/are correct?
2. The vegetative cell is small, spindle-shaped, and floats in the cytoplasm of the generative cell.
3. In species that shed at the 3-celled stage, the generative cell divides mitotically to form two male gametes before shedding.
Which of the above statements is/are correct?
✅ Correct Answer: B
The correct option is B. Statements 1 and 3 are correct, while Statement 2 is incorrect.
When a pollen grain matures, it contains two cells: the vegetative cell and the generative cell.
Structurally, the vegetative cell is much larger, has abundant food reserve, and contains a large, irregularly shaped nucleus.
It is the generative cell that is small, spindle-shaped, and floats within the cytoplasm of the vegetative cell, making Statement 2 an inverse of the facts.
Historically, the evolutionary split between 2-celled and 3-celled shedding has been a recurrent examination concept.
In the approximately 40 percent of species that do not shed at the 2-celled stage, a causal mechanism accelerates male gamete formation: the generative cell undergoes mitosis to produce two non-motile male gametes prior to the anther's dehiscence, ensuring immediate readiness for double fertilization upon reaching the stigma.
When a pollen grain matures, it contains two cells: the vegetative cell and the generative cell.
Structurally, the vegetative cell is much larger, has abundant food reserve, and contains a large, irregularly shaped nucleus.
It is the generative cell that is small, spindle-shaped, and floats within the cytoplasm of the vegetative cell, making Statement 2 an inverse of the facts.
Historically, the evolutionary split between 2-celled and 3-celled shedding has been a recurrent examination concept.
In the approximately 40 percent of species that do not shed at the 2-celled stage, a causal mechanism accelerates male gamete formation: the generative cell undergoes mitosis to produce two non-motile male gametes prior to the anther's dehiscence, ensuring immediate readiness for double fertilization upon reaching the stigma.