Which is not a physiological effect of auxins?

Options

A. Cell elongation
B. Development of parthenocarpic fruits
C. Prevention of abscission of leaves and fruits
D. Reversal of genetic dwarfism

Answer

To determine which option is not a physiological effect of auxins, we can analyze each option based on the known functions of auxins in plant physiology.

### Step-by-Step Solution:

1. **Understanding Auxins**: Auxins are a class of plant hormones that play a crucial role in regulating various physiological processes in plants, including growth and development.

2. **Evaluating the Options**:
- **Cell Elongation**: Auxins promote cell elongation, which is a well-documented physiological effect. This is one of the primary functions of auxins, helping plants grow taller and develop.
- **Development of Parthenocarpic Fruits**: Auxins are known to promote parthenocarpy, which is the development of fruit without fertilization. This is another recognized effect of auxins.
- **Prevention of Abscission of Leaves and Fruits**: Auxins help prevent the premature dropping (abscission) of leaves and fruits, particularly in young plants. This is also a physiological effect of auxins.
- **Reversal of Genetic Dwarfism**: This option refers to the ability to reverse genetic dwarfism, which is not a recognized function of auxins. Genetic dwarfism is typically a result of genetic factors, and while auxins can influence growth, they cannot reverse genetic traits.

3. **Conclusion**: Based on the analysis, the option that is not a physiological effect of auxins is **"Reversal of genetic dwarfism."**

### Final Answer:
**Reversal of genetic dwarfism** is not a physiological effect of auxins.

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