Which of the following functions is not performed by ethylene ?

Options

A. Inhibiting longitudinal growth
B. Inducing ripening of fruits
C. Inducing parthenocarpy
D. Inhibiting geotropism

Answer

To determine which function is not performed by ethylene, we will analyze each of the options provided in the question.

### Step-by-Step Solution:

1. **Understanding Ethylene**: Ethylene is a plant hormone that plays a crucial role in various physiological processes, particularly in fruit ripening and growth regulation.

2. **Analyzing the Options**:
- **Option 1: Inhibiting the longitudinal growth**: Ethylene is known to inhibit longitudinal growth in plants. This is part of its role in promoting maturation and ripening. Therefore, this function is performed by ethylene.

- **Option 2: Inducing ripening of fruit**: Ethylene is famously known for its role in the ripening of fruits. It accelerates the ripening process, which is a significant function of this hormone. Thus, this function is also performed by ethylene.

- **Option 3: Inducing parthenocarpy**: Parthenocarpy refers to the development of fruit without fertilization, and it is primarily induced by auxins, not ethylene. Therefore, this function is not performed by ethylene.

- **Option 4: Inhibiting geotropism**: Ethylene can influence the growth direction of roots and shoots, including inhibiting geotropism. This means it can affect how roots grow in response to gravity, which is a function of ethylene.

3. **Conclusion**: After analyzing all the options, we find that the function that is not performed by ethylene is **inducing parthenocarpy**.

### Final Answer:
The function that is not performed by ethylene is **inducing parthenocarpy**.