Transpiration as percentage of evaporation is called

Options

A. Transpiration index
B. Transpiration ratio
C. Water requirement
D. Transpiration coefficient.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term that describes transpiration as a percentage of evaporation. This indicates we are looking for a specific index or ratio that relates these two processes.

2. **Identifying the Options**: The options provided are:
- A) Transpiration Index
- B) Transpiration Ratio
- C) Water Requirement
- D) Transpiration Coefficient

3. **Analyzing Each Option**:
- **Transpiration Index**: This term is used to describe the relative efficiency of transpiration compared to physical evaporation. It specifically refers to the percentage of evaporation that is accounted for by transpiration.
- **Transpiration Ratio**: This refers to the mass of water transpired relative to the mass of dry matter produced, which does not directly answer the question.
- **Water Requirement**: This term generally refers to the total amount of water needed for plant growth, not specifically related to the percentage of evaporation.
- **Transpiration Coefficient**: This is a measure of the potential transpiration in relation to reference crop evaporation, but again, it does not directly address the percentage of evaporation.

4. **Selecting the Correct Answer**: Based on the definitions and the context of the question, the correct answer is **Transpiration Index**. This term specifically refers to transpiration as a percentage of evaporation.

5. **Conclusion**: Therefore, the answer to the question "Transpiration as percentage of evaporation is called" is **Transpiration Index**.

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