`alpha`-amylase synthesis is promoted by

Options

A. IAA
B. GA
C. Cytokinin
D. NAA.

Answer

To answer the question regarding what promotes the synthesis of `alpha`-amylase, we can follow these steps:

### Step 1: Understand the Role of `alpha`-amylase
`alpha`-amylase is an enzyme that plays a crucial role in the process of seed germination. It helps in the breakdown of starches into sugars, which are essential for the growing seedling.

**Hint:** Remember that enzymes like `alpha`-amylase are critical during the early stages of plant growth, particularly in seed germination.

### Step 2: Identify the Hormones Involved
During seed germination, various plant hormones are involved in regulating the synthesis of enzymes. One of the key hormones that promote the synthesis of `alpha`-amylase is gibberellin.

**Hint:** Focus on the specific hormones that are known to influence enzyme production during germination.

### Step 3: Mechanism of Action
Gibberellins stimulate the production of messenger RNA (mRNA), which in turn directs the synthesis of hydrolytic enzymes, including `alpha`-amylase. This process is essential for mobilizing stored nutrients in the seed.

**Hint:** Think about how hormones interact with genetic material to produce enzymes.

### Step 4: Eliminate Other Options
While other hormones such as indole acetic acid (IAA), cytokinins, and naphthalene acetic acid (NAA) are important in plant growth, they do not specifically promote the synthesis of `alpha`-amylase during seed germination.

**Hint:** Compare the roles of different hormones and focus on their specific functions related to enzyme synthesis.

### Conclusion
Based on the information gathered, we conclude that the synthesis of `alpha`-amylase is promoted by gibberellins.

**Final Answer:** Gibberellins promote the synthesis of `alpha`-amylase.