On some aspects of photosynthesis revealed by photoacoustic studies: a critical evaluation

Photoacoustic techniques have been widely developed in photosynthesis research since the 1970s. We can divide the progress in this field into three periods. In the first period, a pioneer, William W. Parson (and his co-workers) discovered that the photochemical charge separation is accompanied by a conformation change. In the second period, the technique was essentially used to measure the two components of photochemical activity detected in the gas phase: energy storage (photothermal effect) and gas exchange (photobaric effect). In the third period, the time resolution and sensitivity of detection in liquid phase were significantly improved. In reviewing this last period, we shall focus on three aspects: conformation changes, thermodynamic parameters, and quantum yield spectra.