Which of the following is required for auxin synthesis?

Options

A. Calcium
B. Zinc
C. Sugars
D. Proteins

Answer

To determine which element is required for auxin synthesis, we can analyze the options provided:

1. **Calcium**: Calcium plays a significant role in the formation of cell membranes and overall plant growth. However, it is not directly involved in auxin synthesis.

2. **Zinc**: Zinc is crucial for the synthesis of auxin, specifically indole-3-acetic acid (IAA), which is a primary plant growth hormone. Zinc acts as a precursor for tryptophan, an amino acid that is necessary for auxin production. Therefore, zinc is essential for auxin synthesis.

3. **Sugars**: While sugars are vital for energy and metabolism in plants, they do not have a direct role in the synthesis of auxin.

4. **Proteins**: Proteins are fundamental to many biological processes, including hormone synthesis. However, the specific requirement for auxin synthesis is linked to zinc, making this option less relevant in this context.

Based on this analysis, the correct answer is **Zinc**.

### Step-by-Step Solution:
1. **Identify the options**: The question provides four options: Calcium, Zinc, Sugars, and Proteins.

2. **Evaluate Calcium**: Understand that while calcium is important for cell structure, it is not directly related to auxin synthesis.

3. **Evaluate Zinc**: Recognize that zinc is necessary for the formation of tryptophan, which is a precursor for auxin (IAA). Therefore, zinc is required for auxin synthesis.

4. **Evaluate Sugars**: Acknowledge that sugars are essential for energy but do not play a direct role in auxin synthesis.

5. **Evaluate Proteins**: Understand that while proteins are involved in many biological processes, they are not the specific requirement for auxin synthesis compared to zinc.

6. **Conclusion**: Based on the evaluations, conclude that zinc is the element required for auxin synthesis.