When grown under ambient CO2 and assayed under growth
temperature (23 ◦C), high light (900 mol m−2 s−1) and ambient
CO2 (370 ppm) all three plant lines exhibited a stimulation in photosynthesis
when the O2 content was reduced from 21% to 2%,
although the extent of stimulation varied considerably among the
three plant lines. Ambient CO2-grown TLUp1-9 showed a larger stimulation
in photosynthetic rate than WT under low O2 indicating that
it had a greater capacity for triose-P utilization (Fig. 3A). In turn,
TL46, which has the lowest capacity for starch synthesis, exhibited
the lowest stimulation of O2 sensitivity.