Table II.

Effects of O2 on net CO2 assimilation in wild-type and low GO maize leaves

Rates of A were first measured in 1% O2 as described in “Materials and Methods.” Shown are the initial and final (i.e. 40–50 min later) values of A recorded after raising the O2 level to 50%. Values in parentheses each represent the percent recovery of A relative to the preceding rate measurement. The Fv/Fm was measured at the beginning of the experiment after 12 h of dark adaptation. Values are means (±se) for three replicate leaves.

ParameterWild TypeLow GO
A (1% O2)9.64 ± 1.287.96 ± 0.37
Initial A (50% O2)8.93 ± 0.89 (96.2% ± 0.3)7.70 ± 0.37 (96.8% ± 0.6)
Final A (50% O2)7.91 ± 1.48 (83.9% ± 5.8)a0.54 ± 0.09 (7.0% ± 1.1)
Fv/Fm0.744 ± 0.0040.689 ± 0.029
  • a A significant difference due to phenotype based on a T test (P < 0.05).