Which process is not directly affected by auxin?

Options

A. Apical dominance and root initiation
B. Parthenocarpy
C. Synthesis of `alpha`-amylase by barley seeds
D. Leaf abscission

Answer

To determine which process is not directly affected by auxin, we need to analyze the options provided in the question:

1. **Apical Dominance and Root Initiation**: Auxin plays a crucial role in promoting apical dominance, which is the phenomenon where the main central stem of the plant grows more strongly than the side stems. It also promotes root initiation.

2. **Parthenocarpy**: Auxin is involved in the development of seedless fruits (parthenocarpy). It stimulates the growth of the ovary into a fruit without fertilization.

3. **Synthesis of Alpha Amylase by Barley Seed**: Auxin does not directly influence the synthesis of alpha amylase in barley seeds. This process is more related to the plant's response to gibberellins rather than auxins.

4. **Leaf Abscission**: Auxin affects leaf abscission by preventing it. It helps in retaining leaves and flowers, thus it has a direct role in this process.

Based on this analysis, the process that is not directly affected by auxin is:

**Synthesis of Alpha Amylase by Barley Seed.**

### Step-by-Step Solution:
1. **Identify the Role of Auxin**: Understand that auxin is a plant hormone that regulates various growth processes.
2. **Evaluate Each Option**: Analyze how auxin influences each of the processes listed in the options.
- Apical dominance and root initiation: Auxin promotes these processes.
- Parthenocarpy: Auxin is involved in this process.
- Synthesis of alpha amylase by barley seed: This process is not directly influenced by auxin.
- Leaf abscission: Auxin prevents leaf abscission.
3. **Conclusion**: Determine which process is least affected by auxin, which leads to the conclusion that the synthesis of alpha amylase by barley seed is the correct answer.