Pollen grains in Angiosperms are released at which stage?

Options

A. 1-celled
B. 2-celled
C. 3-celled
D. 2 or 3-celled

Answer

**Step-by-Step Solution:**

1. **Understanding Pollen Grain Development**: Pollen grains in angiosperms (flowering plants) develop from microspores through a process called microgametogenesis.

2. **Stages of Pollen Grain Formation**: Pollen grains can be released at different stages of development. The two primary stages are the 2-celled stage and the 3-celled stage.

3. **2-Celled Stage**: In the 2-celled stage, the pollen grain consists of two cells:
- One vegetative cell (which will form the pollen tube).
- One generative cell (which will eventually divide to form male gametes).

4. **3-Celled Stage**: In the 3-celled stage, the generative cell undergoes mitosis before pollen grain release, resulting in:
- One vegetative cell.
- Two male gametes.

5. **Percentage of Angiosperms**: Approximately 60% of angiosperms release their pollen at the 2-celled stage, while about 40% release at the 3-celled stage.

6. **Conclusion**: Therefore, pollen grains in angiosperms are typically released at either the 2-celled or 3-celled stage, making the most appropriate answer the 2 to 3-celled stage.

**Final Answer**: Pollen grains in angiosperms are released at the 2 to 3-celled stage.

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