Herritt et al 2020 demonstrate the PSII camera's ability to capture PSII fluorescence by treating leaves with a chemical that inhibits photosynthesis (DMCU) and observing differences.
Herritt, M.T., Pauli, D., Mockler, T.C. et al. Chlorophyll fluorescence imaging captures photochemical efficiency of grain sorghum (Sorghum bicolor) in a field setting. Plant Methods 16, 109 (2020). https://doi.org/10.1186/s13007-020-00650-0