In a classic experiment to describe the first action spectrum of photosynthesis, T.W. Engelmann illuminated a green alga placed in a suspension. Which of the following was used by him to specifically detect the sites of oxygen evolution?

Step-by-step solution

T.W. Engelmann performed an experiment using a green alga, Cladophora, placed in a suspension of aerobic bacteria. He used a prism to split light into its spectral components and illuminated the alga. The aerobic bacteria were used to detect the sites of oxygen evolution, as they accumulate in areas where oxygen is being produced. He observed that the bacteria accumulated mainly in the regions of blue and red light, which correspond to the absorption spectra of chlorophyll a and b, thus describing the first action