The plant factor which is inversely proportional to transpiration is

Options

A. Root shoot ratio
B. Shoot root ratio
C. Stomatal frequency
D. Size of the leaf

Answer

To solve the question regarding the plant factor that is inversely proportional to transpiration, we can follow these steps:

### Step-by-Step Solution

1. **Understand Transpiration**: Transpiration is the process by which water is lost from the plant, primarily through small openings in the leaves called stomata. It is influenced by various factors including environmental conditions and plant characteristics.

2. **Identify Plant Factors**: The question asks for a plant factor that affects transpiration. Some of the plant factors include root-shoot ratio, stomatal frequency, and leaf size.

3. **Analyze Root-Shoot Ratio**:
- The root-shoot ratio refers to the relative sizes of the root system compared to the shoot system (stems and leaves).
- A higher root surface area allows for more water absorption, which can lead to increased transpiration.

4. **Consider Shoot-Root Ratio**:
- The shoot-root ratio is the opposite, where the shoot system has a larger surface area compared to the roots.
- In this scenario, if the shoot has a larger surface area but the roots have a smaller surface area, less water can be absorbed.

5. **Establish the Relationship**:
- If the shoot-root ratio is high (more shoot surface area), it means that the root surface area is relatively low, leading to less water absorption.
- Consequently, with less water available for transpiration, the transpiration rate decreases.

6. **Conclusion**: Therefore, the shoot-root ratio is inversely proportional to transpiration. As the shoot-root ratio increases, the rate of transpiration decreases.

### Final Answer
The plant factor which is inversely proportional to transpiration is the **shoot-root ratio**.

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