variation in CO2 assimilation rates between plants, O2 sensitivity
measurements showed consistent and significant differences
in photosynthetic capacity between WT and transgenic rice lines
(Fig. 4). WT plants showed a relatively small increase in CO2 assimilation
when O2 levels were decreased from 21% to 2% suggestive
of feedback limitation on photosynthesis; whereas, the three transgenic
rice lines showed stimulation of 25–35% under low O2. This
increase in stimulation by low O2 indicates that the transgenic rice
lines have greater photosynthetic capacity and are less subject to
feedback.