Some experiments were carried out using Croton sp. plants to understand the process of photosynthesis. It was observed that the leaves of the plant exposed to light for longer duration accumulated more starch. However, due to presence of pre-formed starch in the leaves, it was difficult to find the net productivity on a fixed exposure to light source. Therefore, it was necessary to obtain starch free leaves in the plant before starting the experiment.
Which of the following would help obtain starch free leaves in the plant?

Options

A. Expose the leaves to blue light for 48 hours before starting the experiment.
B. Keep the plant in dark for about 48 hours before starting the experiment.
C. Remove starch from the leaves by exosmosis, 48 hours before starting the experiment.
D. Keep the leaves to red light for 48 hours before starting the experiment.

Explanation

To obtain starch-free leaves in Croton sp. plants before conducting experiments on photosynthesis, follow these steps:

1. **Understand the Requirement**: The goal is to have leaves that do not contain any pre-formed starch, which can interfere with measuring the net productivity of photosynthesis.

2. **Identify the Problem**: The presence of starch in leaves makes it difficult to assess the net productivity of photosynthesis under fixed light exposure. Therefore, we need to eliminate any existing starch.

3. **Choose the Correct Method**: The most effective way to obtain starch-free leaves is to deprive the plant of light. Since starch is produced during photosynthesis, keeping the leaves in darkness will prevent starch accumulation.

4. **Implement the Method**: Keep the leaves in the dark for about 48 hours before starting the experiment. This duration is sufficient for the plant to utilize the existing starch reserves, thus leading to starch-free leaves.

5. **Conclusion**: After keeping the leaves in the dark for 48 hours, they will be free from starch, allowing for accurate measurements of starch production during the experiment.