Table 5.

Summary of ANOVA results for effects of elevated CO₂ and increased nitrogen fertilization on digestive and protective system enzymes of Ostrinia furnacalis.

Measurement	Treatment	df	F	P
Trypsin	CO2	1	2.78	0.13
	N	2	13.86	<0.01
	CO2∗N	2	0.95	0.43
Total protease	CO2	1	4.09	0.08
	N	2	10.48	<0.01
	CO2∗N	2	0.85	0.46
Amylase	CO2	1	7.55	0.02
	N	2	10.88	<0.01
	CO2∗N	2	0.55	0.6
Lipase	CO2	1	0.67	0.43
	N	2	2.02	0.19
	CO2∗N	2	1.23	0.34
CAT	CO2	1	0.1	0.76
	N	2	7.05	0.02
	CO2∗N	2	0.04	0.96
POD	CO2	1	4.23	0.07
	N	2	1.02	0.40
	CO2∗N	2	1.07	0.39
SOD	CO2	1	6.86	0.03
	N	2	6.19	0.02
	CO2∗N	2	0.81	0.48

^∗CAT, catalase; POD, peroxidase; SOD, superoxide dismutase, N, low N fertilization level (100 mg N/kg soil mixture), middle N fertilization level (200 mg N/kg soil mixture), and high N fertilization level (300 mg N/kg soil mixture); CO₂, ambient CO₂ concentrations (∼380 ppm) and elevated CO₂ concentrations (∼750 ± 15 ppm); n = 3.