Table I. Normalized changes of activities of enzymes in plants treated with PAC and/or GA grown at 350 or 750 µmol CO2 mol−1

For each treatment (Figs. 3 and 4), the activities were related to protein and the activity of 750 µmol CO2 mol−1 was divided by the activity of 350 µmol CO2 mol−1. Values in boldface were determined by Student’s t test to be significantly different from the control. Values are means ± se of four independent experiments.

Enzyme Activity (Activity in Elevated CO2 as a Percentage of Ambient CO2)
EnzymeControlGAPACPAC + GA
Rubisco, initial101.3 ± 7.3104.9 ± 9.4126.5 ± 5.3110.4 ± 9.5
Rubisco, total103.1 ± 4.0109.3 ± 4.4137.7 ± 7.1115.7 ± 10.8
GAPDH (NADP)126.7 ± 9.0118.3 ± 10.1126.0 ± 10.2113.5 ± 8.7
AGPase224.4 ± 13.9252.1 ± 15.5221.9 ± 13.0243.5 ± 17.5
TK109.8 ± 9.0123.2 ± 9.4162.6 ± 8.3109.8 ± 5.9
Aldolase120.9 ± 5.7118.0 ± 6.5120.8 ± 8.1127.7 ± 9.1
PGK111.4 ± 4.7118.1 ± 6.7148.2 ± 7.2129.6 ± 6.8
NR96.6 ± 8.0104.2 ± 10.3151.8 ± 8.9109.1 ± 8.8
MDH (NAD)220.2 ± 17.9254.4 ± 20.8149.1 ± 12.0201.0 ± 15.7
MDH (NADP), initial104.5 ± 4.9106.6 ± 7.2104.6 ± 4.4119.3 ± 10.6
Total98.5 ± 4.6100.7 ± 9.181.1 ± 5.1103.3 ± 6.3