Investigating on relationship between effective quantum efficiency and irradiance

AbstractModels describing the relationship between effective quantum efficiency of PS II ({Phi}PSII) and irradiance (I) are routinely used to determine how irradiance influences effective quantum efficiency and photosynthetic electron transport rate (ETR). However, with no single model one can accurately describe the relationship between{Phi} PSII and I, and explain the interdependence between{Phi} PSII and biophysical properties of photosynthetic pigments, especially in plants growing under low level irradiances. Basing on the mechanistic model of photosynthetic electron transport rate we have developed the model of the relationship between{Phi} PSII and I. The new model reveals that{Phi} PSII increases with photochemistry (kP) and heat dissipation (kD). Furthermore, the values of key parameters calculated using the new model were compared with the values calculated with two other empirical models. The new model was perfectly fitted to the light-response curves of{Phi} PSII. The key calculated photosynthetic parameters: maximum{Phi} PSII, maximum ETR and their corresponding saturation irradiance were close to the measured values. In addition, our model associates{Phi} PSII with intrinsic features of photosynthetic pigments. We concluded that{Phi} PSII decreased with increasing I due to the decrease in the effective absorption cross-section of photosynthetic pigments molecules.\n\nHighlightA model of the relationship between effective quantum efficiency of PS II ({Phi}PSII) and irradiance (I) has been developed. Using this new model it was found that{Phi} PSII decreased with increasing I due to the decrease in the effective absorption cross-section of photosynthetic pigments molecules.\n\nAbbreviations