In which green alga, action spectrum of photosynthetic pigments was studied by Engelmann ?

Options

A. Nostoc
B. Cladophora
C. Chlorella
D. Scenedesmus

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the specific green alga in which T.W. Engelmann studied the action spectrum of photosynthetic pigments.

2. **Identifying the Researcher**: T.W. Engelmann is the key figure in this study. He is known for his experiments related to photosynthesis.

3. **Method Used by Engelmann**: Engelmann used a prism to split white light into its spectral components. This allowed him to illuminate the algae with different wavelengths of light.

4. **Type of Alga Used**: The specific green alga that Engelmann used for his experiment was **Cladophora**.

5. **Experimental Setup**: Engelmann placed Cladophora in a suspension of aerobic bacteria. The aerobic bacteria were used to detect the sites of oxygen production.

6. **Observations Made**: Engelmann observed that the aerobic bacteria accumulated in areas illuminated by blue and red light. This indicated that these wavelengths were most effective for photosynthesis.

7. **Conclusion**: Engelmann's experiment led to the conclusion that chlorophyll absorbs light primarily in the blue and red regions of the spectrum, which is crucial for the process of photosynthesis.

8. **Final Answer**: The green alga in which Engelmann studied the action spectrum of photosynthetic pigments is **Cladophora**.

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