In maize grain, the plumule remains covered by a protective sheath called coleorhiza.

Answer

**Step-by-Step Solution:**

1. **Understanding Maize Grain**: Maize grain is classified as a monocot seed. This means it has a single cotyledon and specific structures that protect the developing plant.

2. **Structure of Maize Grain**: The maize grain consists of several parts:
- **Endosperm**: This is the nutrient-rich tissue that provides food for the developing embryo. It is made up of two layers:
- **Allurone Layer**: The outer layer that contains proteins.
- **Starch**: The inner layer that is primarily composed of carbohydrates.

3. **Cotyledon**: In maize, the cotyledon is referred to as the **scutellum**. It is thin and papery, which is characteristic of monocot seeds.

4. **Embryonal Axis**: The embryonal axis consists of two main parts:
- **Plumule**: This is the part of the embryo that will develop into the shoot of the plant.
- **Radical**: This is the part that will develop into the root.

5. **Protective Sheaths**:
- The **plumule** is covered by a protective sheath called **coleoptile**.
- The **radical** is covered by a protective sheath called **coleorhiza**.

6. **Analyzing the Statement**: The statement claims that in maize grain, the plumule is covered by a sheath called coleorhiza. This is incorrect because:
- The plumule is actually covered by the coleoptile.
- The coleorhiza is the protective covering for the radical, not the plumule.

7. **Conclusion**: Therefore, the statement is false. In maize grain, the plumule is covered by the coleoptile, while the coleorhiza covers the radical.

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