Who among the following scientists first gave the starch sugar interconversion theory for stomatal movements ?

Options

A. Loftfield
B. Lloyd
C. Sayre
D. Von Mohl

Answer

To answer the question regarding who first proposed the starch-sugar interconversion theory for stomatal movements, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Question**: The question asks for the scientist who first proposed the starch-sugar interconversion theory related to stomatal movements.

2. **Review the Options**: The options provided are:
- A) Lockheed
- B) Lloyd
- C) Siree
- D) Vaughan Moll

3. **Recall Relevant Theories**: There are several theories regarding stomatal movements. Notably, the starch-sugar interconversion theory is one of them.

4. **Determine the Origin of the Theory**: According to the information provided:
- The starch-sugar interconversion theory was first proposed by Lloyd in 1908.

5. **Verify Additional Information**: It is mentioned that Lockheed supported this theory in 1921, but he did not propose it.

6. **Conclude the Answer**: Based on the information, the correct answer is Lloyd, as he was the first to propose the starch-sugar interconversion theory.

### Final Answer:
**Option B: Lloyd**