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Figure 1. Effects of CO2 and O3 on average net photosynthesis (A) of upper canopy leaves of peanut from 8 through 19 wk after planting in the 2-yr experiment (A, B). Seasonal average A is also shown (C). Treatments included charcoal-filtered air (CF)–ambient CO2 (CF-375) (control), CF air plus 355 µmol CO2 mol–1 (CF-730), nonfiltered air (NF)–ambient CO2 (NF-375), NF air plus 355 µmol CO2 mol–1 (NF-730), NF air plus 634 µmol CO2 mol–1 (NF-1009), 1.5 x ambient O3–ambient CO2 (OZ-375), and 1.5 x ambient O3 plus 355 µmol CO2 mol–1 (OZ-730). Values are means ± SE from two or three replicate chambers per treatment in each year of the experiment (see Table 1). Values above the bars in panel C indicate percentage of the control treatment. Significant treatment effects are indicated as P 
0.05 (*), P 0.01 (**), and P 0.001 (***).
