2.6. Data analysis
SPSS 13.0 (SPSS Inc., United States) was used in the calculationof a custom nonlinear regression model for photosynthesis lightcurves of non-rectangular hyperbola fitting. One-way-analysis ofvariance using SPSS13.0 and the multiple comparisons with Dun-can’s test were used to determine the mean differences in thephotosynthetic parameters among N treatments. Plot 12.5 (SPSSInc., United States) was employed in the linear regression analy-sis of the 0−150 mol m−2s−1photosynthesis-light data and linearregression analysis between flag leaf photosynthetic and biologicalparameters. Plot 12.5 was also used to make the figures in thismanuscript.