Which of the following elements is essential for synthesis of IAA ?

Options

A. Fe
B. Zn
C. B
D. Mn

Answer

To determine which element is essential for the synthesis of Indole-3-acetic acid (IAA), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the essential element required for the synthesis of IAA, which is a plant hormone known as auxin.

2. **Identify the Elements**: The options provided in the question include elements such as zinc, iron, boron, and manganese.

3. **Research the Role of Each Element**:
- **Zinc (Zn)**: It is known to be an essential micronutrient that plays a crucial role in various biochemical processes, including the synthesis of IAA.
- **Iron (Fe)**: While important for many plant functions, it is not directly involved in the synthesis of IAA.
- **Boron (B)**: This element is essential for cell wall formation and reproductive development but does not directly contribute to IAA synthesis.
- **Manganese (Mn)**: It is involved in photosynthesis and enzyme activation but is not essential for IAA synthesis.

4. **Conclude the Essential Element**: Based on the research, zinc is identified as the essential element for the synthesis of IAA. It is necessary for the activity of certain enzymes involved in the production of this hormone.

5. **Final Answer**: The element essential for the synthesis of IAA is **Zinc (Zn)**.