Essentiality of light in photosynthesis can be demonstrated by

Options

A. Molles half leaf experiment
B. Ganong screen
C. Inverted funnel experiment
D. KOH solution

Answer

To demonstrate the essentiality of light in photosynthesis, we can follow these steps based on the Gyanong's Light Screen Experiment:

### Step-by-Step Solution:

1. **Understanding Photosynthesis**:
- Photosynthesis is the process by which green plants convert light energy into chemical energy, producing glucose and oxygen from carbon dioxide and water. This process primarily occurs in the leaves, where chlorophyll is present.

2. **Setting Up the Experiment**:
- The experiment involves taking a green plant, specifically one that has been previously starched (meaning it has stored starch in its leaves).

3. **Dark Treatment**:
- Place the green plant in a dark room for 48 hours. This step is crucial as it ensures that the plant does not receive any light, which is essential for photosynthesis.

4. **Testing for Starch**:
- After the dark treatment, test the leaves of the plant for the presence of starch. This can be done using iodine solution, which turns blue-black in the presence of starch.

5. **Observation**:
- The leaves of the plant that were kept in the dark will show no blue-black coloration, indicating that they are starch-free. This means that without light, the plant could not perform photosynthesis and thus did not produce starch.

6. **Light Treatment**:
- In a separate part of the experiment, keep another green plant in light conditions. This plant will be able to perform photosynthesis.

7. **Testing Again**:
- After a similar period of exposure to light, test the leaves of this plant for starch using the iodine solution.

8. **Conclusion**:
- The leaves of the plant kept in light will turn blue-black, indicating the presence of starch. This demonstrates that light is essential for photosynthesis, as it provides the energy needed for the process.

### Final Conclusion:
The essentiality of light in photosynthesis can be demonstrated by Gyanong's Light Screen Experiment, where plants kept in the dark do not produce starch, while those kept in light do.