Warburg effect has not been observed in

Options

A. Maize
B. Sugarcane
C. Sorghum
D. All of these

Answer

### Step-by-Step Solution:

1. **Understanding the Warburg Effect**: The Warburg effect refers to the phenomenon where there is a decrease in the rate of photosynthesis in plants due to high concentrations of oxygen. This effect leads to a shift from photosynthesis to photorespiration, where plants utilize oxygen and produce carbon dioxide instead of using carbon dioxide to produce glucose.

2. **Identifying the Conditions**: The Warburg effect is primarily observed in C3 plants. In these plants, high levels of oxygen can inhibit the process of photosynthesis because the presence of oxygen leads to photorespiration, which is less efficient than photosynthesis.

3. **Differentiating Plant Types**: There are two main types of plants based on their photosynthetic pathways: C3 plants and C4 plants. C4 plants, such as maize, sugarcane, and sorghum, have adaptations that allow them to avoid the Warburg effect. They maintain a constant concentration of carbon dioxide and oxygen, which prevents the occurrence of photorespiration.

4. **Analyzing the Given Options**: The question provides options: maize, sugarcane, sorghum, or all of these. Since all these plants are classified as C4 plants, they do not exhibit the Warburg effect.

5. **Conclusion**: Therefore, the Warburg effect has not been observed in maize, sugarcane, or sorghum, as they are all C4 plants.

### Final Answer:
The Warburg effect has not been observed in **all of these (maize, sugarcane, sorghum)**.