The experimental material that has largely been responsible for making rapid advances in research on photosynthesis is

The experimental material that has largely been responsible for making rapid advances in research on photosynthesis is Chlorella.
Chlorella is a genus of about thirteen species of single-celled green algae belonging to the division Chlorophyta.
In 1961, Melvin Calvin of the University of California received the Nobel Prize in Chemistry for his research on the pathways of carbon dioxide assimilation in plants using Chlorella.
The experimental research was carried out in laboratories, rather than in the field, and scientists discovered that Chlorella would be much more difficult to produce than previously thought.