Figure 5. Leaf CO₂ exchange rate (CER) of maize hybrids Pride 5, Pioneer 3902, and Cargill 1877 from tassel emergence to 6 wk after silking. Data shown are measurements taken at 1200 h on the day following the night of cold exposure. Vertical bars are standard errors of the mean. (Adapted from Ying et al., 2000.)