2.4 Statistical analysis
The generalized linear model (GLM) multivariate procedure from SPSS
software (Ver22, IBM, Armonk, NY, USA) was used for the ANOVA to test
the effects among the treatments. The CO2 level, N
supply rate and tissue type were defined as independent factors, and
their full interactions were analyzed using the GLM procedure.
Significance level was set at (p ≤0.05) for post-hoc test. Data
presented in figures and tables were the average ± standard deviation.