An enzyme that can stimulate germination of barley seeds is

Options

A. (a) invertase
B. (b) `alpha` amylase
C. (c) lipase
D. (d) protease

Answer

To answer the question regarding the enzyme that stimulates the germination of barley seeds, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Seed Structure**:
- Barley seeds have an outer protective covering known as the seed coat, which protects the embryo inside.

2. **Conditions for Germination**:
- Germination occurs when the conditions are favorable, which typically include the presence of water and suitable temperatures (around 15 to 25 degrees Celsius).

3. **Role of Water**:
- When water is absorbed by the seed, it triggers various biochemical processes. This process is known as imbibition.

4. **Release of Gibberellins**:
- The absorption of water leads to the release of a plant hormone called gibberellin. Gibberellins play a crucial role in breaking seed dormancy and promoting germination.

5. **Action of Gibberellins**:
- Gibberellins stimulate the production of specific enzymes necessary for breaking down stored nutrients in the seed.

6. **Enzyme Involved**:
- One key enzyme that is stimulated by gibberellins is **alpha-amylase**. This enzyme is responsible for breaking down starch, which is the primary stored nutrient in the seed coat.

7. **Conversion of Starch to Sugar**:
- Alpha-amylase catalyzes the hydrolysis of starch into simpler sugars, such as glucose, which are essential for the energy needs of the growing embryo during germination.

8. **Conclusion**:
- Therefore, the enzyme that stimulates the germination of barley seeds is **alpha-amylase**.

### Final Answer:
The enzyme that can stimulate germination of barley seeds is **alpha-amylase**.

---