In Xanthium and many grasses seed dormancy occurs due to

Options

A. Impermeability of seed coats to oxygen
B. Impermeability of seed coats to water
C. Immaturity of embryo
D. Germination inhibitor

Answer

**Step-by-Step Solution:**

1. **Understanding Seed Dormancy**:
- Seed dormancy refers to a state in which seeds do not germinate even under favorable conditions. This delay in germination can be due to various factors.

2. **Identifying Causes of Seed Dormancy**:
- There are several reasons that can lead to seed dormancy:
- The seed coat may be impermeable to oxygen.
- The seed coat may be impermeable to water.
- The embryo may be immature.
- The presence of germination inhibitors.

3. **Focusing on Xanthium and Grasses**:
- In the case of Xanthium and many grasses, the primary cause of seed dormancy is identified.

4. **Determining the Specific Cause**:
- For Xanthium and many grasses, the specific reason for seed dormancy is the impermeability of the seed coat to oxygen. This means that the seeds cannot take in the oxygen necessary for the germination process.

5. **Conclusion**:
- Therefore, the correct answer to the question regarding the cause of seed dormancy in Xanthium and many grasses is that it occurs due to the impermeability of the seed coat to oxygen.

**Final Answer**: The seed dormancy in Xanthium and many grasses occurs due to the impermeability of the seed coat to oxygen.

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