A new model for relationship between irradiance and the rate of photosynthesis in Oryza sativa

The calculated maximum net photosynthetic rate (P N) at saturation irradiance (I m) of 1 314.13 µmol m-2 s-1 was 25.49 µmol(CO2) m-2 s-1, and intrinsic quantum yield at zero irradiance was 0.103. The results fitted by nonrectangular hyperbolic model, rectangular hyperbolic method, binomial regression method, and the new model were compared. The maximum P N values calculated by nonrectangular hyperbolic model and rectangular hyperbolic model were higher than the measured values, and the I m calculated by nonrectangular hyperbolic model and rectangular hyperbolic model were less than measured values. Results fitted by new model showed that the response curve of P N to I was nonlinear at low I for Oryza sativa, P N increased nonlinearly with I below saturation value. Above this value, P N decreased nonlinearly with I.