We establish a system to measure the functional absorption cross section of photosystem II (PSII) (σ<sub>PSII</sub>) and maximum quantum yield of photochemistry in PSII (<i>F</i><sub>v</sub>/<i>F</i><sub>m</sub>). The system utilizes a sequence of high-frequency excitation flashes at microsecond intervals to induce a microsecond-level fluorescence yield curve. Parameters σ<sub>PSII</sub> and <i>F</i><sub>v</sub>/<i>F</i><sub>m</sub> are calculated by fitting the curve using nonlinear regression. Experimental results show that the relative standard deviation (RSD) of the system is less than 3%, and the correlation coefficient of <i>F</i><sub>v</sub>/<i>F</i><sub>m</sub> values measured by this system and those measured by pulse amplitude modulation method is 0.950.
© 2014 Chinese Optics LettersPDF Article