In angiosperm pollen grains are dehisced at

Options

A. (a) 4 celled stage
B. (b) mostly at 2 and sometimes at 3 called stage
C. (c) 3 called stage
D. (d) pollen tube stage

Answer

**Step-by-Step Solution:**

1. **Understanding Pollen Grain Dehiscence**:
- In angiosperms, pollen grains are released from the anther to the stigma during the process of pollination. This release is referred to as dehiscence.

2. **Pollen Grain Structure**:
- Pollen grains in angiosperms typically exist in a two-cell stage at the time of dehiscence. These two cells are:
- **Generative Cell**: This cell will eventually divide to form two male gametes.
- **Tube Cell**: This cell develops into the pollen tube that will transport the male gametes to the ovary.

3. **Exceptions in Pollen Grain Structure**:
- While most angiosperms have pollen grains in a two-cell stage, some exceptions exist. For example, in wheat, pollen grains can be found in a three-cell stage, which includes:
- One tube cell nucleus
- Two male gametes (formed from the generative cell dividing before pollination).

4. **Analyzing the Options**:
- Option A states "4 cell stage" - This is incorrect.
- Option B states "mostly at 2 and sometimes at 3 cell stage" - This is correct.
- Option C states "3 cell stage" - This is incorrect because it does not account for the majority of angiosperms.
- Option D states "pollen tube stage" - This is incorrect as the pollen tube formation occurs after pollination.

5. **Conclusion**:
- The correct answer is option B: "mostly at 2 and sometimes at 3 cell stage".

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