What will happen when pollen grain is placed in water ?

Options

A. It will germinate and produce a pollen tube
B. The pollen grain does not germinate
C. The pollen grain swells up but bursts at places without forming a pollen tube
D. The pollen grain forms a number of pollen tubes

Answer

**Step-by-Step Solution:**

1. **Understanding Pollen Grains**: Pollen grains are the male gametes in angiosperms (flowering plants). They have a tough outer layer and an inner layer called the intine, which is semi-permeable.

2. **Placing Pollen Grains in Water**: When pollen grains are placed in water, the semi-permeable intine allows water to enter the pollen grain.

3. **Absorption of Water**: As water enters the pollen grain, it begins to swell. This swelling occurs because the intine absorbs water.

4. **Swelling and Bursting**: The swelling of the pollen grain continues until the pressure inside becomes too great. Eventually, the pollen grain may burst at various points due to the excessive internal pressure.

5. **Pollen Tube Formation**: Normally, when pollen grains germinate, they form a pollen tube that allows for the transfer of sperm to the ovule. However, in this case, because the intine bursts, a pollen tube does not form.

6. **Conclusion**: Therefore, when pollen grains are placed in water, they swell up but burst at places without forming a pollen tube. The correct answer is option C.

**Final Answer**: The pollen grain swells up but bursts at places without forming a pollen tube.

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