Table 1.

Analysis of variance (P-values) of midday photosynthetic gas exchange, root respiration, and calculated whole plant carbon balance, following long-term exposure to moderate O₃ in Pima cotton (CHRONIC/GASEX experiment)

	Pima cotton
	O3	MeJA	O3×MeJA
Leaf area (m2 plant−1)	0.008	0.000	0.945
Assimilation (μmol m−2 s−1)	0.001	0.000	0.671
Stomatal conductance (μmol m−2 s−1)	0.000	0.007	0.742
Root respiration (μmol g dwt−1 s−1)	0.941	0.001	0.623
Carbon balance (μmol plant−1)	0.001	0.000	0.469