When castor seeds are placed in a suitable medium for germination , By which of the following first process water enters into the seed coat ?

Options

A. Osmosis
B. Imbibition
C. Absorption
D. Root pressure

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks how water first enters the seed coat of castor seeds when they are placed in a suitable medium for germination.

2. **Identifying the Processes**: The two main processes for water absorption in seeds are:
- **Osmosis**: This is the movement of water across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
- **Imbibation**: This refers to the absorption of water by solid substances, leading to swelling.

3. **Analyzing Imbibation**: When seeds are placed in water, they absorb water through their seed coat. This is primarily due to imbibation, where the dry seed coat takes up water and swells. This process is crucial for initiating germination.

4. **Understanding Osmosis in Context**: While osmosis is a significant process in plants, it generally occurs after imbibation has taken place. In the context of seeds, the initial water uptake is not through osmosis but through imbibation.

5. **Conclusion**: Therefore, the first process by which water enters the seed coat of castor seeds is **imbibation**.

**Final Answer**: The correct answer is **imbibation**.

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