Table II. N-related enzyme activities during pre anthesis in flag leaves.
N-related enzyme activities were determined in flag leaves of wild-type and transgenic PSARK::IPT plants subjected to 3 d of water stress. Enzyme activities are expressed as moles of metabolite generated/consumed per milligram of protein per unit of time. Additional details are provided in “Materials and Methods.” Values are presented as means ± sd of six individual plants per genotype/treatment. The data were analyzed using one-way ANOVA followed by Student’s t test. Boldface values indicate significant differences by genotype comparisons (P ≤ 0.05); asterisks indicate significant differences by treatment comparisons (P ≤ 0.05).
| Enzyme Activities | Flag Leaf |
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|---|---|---|---|---|
| Well Watered |
Water-Stress |
|||
| Wild Type | PSARK::IPT | Wild Type | PSARK::IPT | |
| NR (nmol NO2 mg−1 protein min−1) | 3.2 ± 0.4* | 3.4 ± 0.3 | 1.7 ± 0.5 | 5.1 ± 0.2* |
| NiR (nmol NO2 mg−1 protein min−1) | 98.9 ± 26.1* | 138.1 ± 38.4 | 14.7 ± 8.3 | 118 ± 8 |
| NADH-GOGAT (nmol NADH mg−1 protein min−1) | 7.7 ± 1.2 | 7.3 ± 1.2 | 8. 5 ± 1 | 6.9 ± 0.1 |
| GS (µmol Gln mg−1 protein h−1) | 198.3 ± 53.5 | 191.6 ± 23.1 | 215.4 ± 51.7 | 215.4 ± 26.1 |
| GDH (amination) [nmol NADH mg protein−1 min−1] | 8.1 ± 1.5 | 7.1 ± 1.1 | 6.6 ± 0.6 | 6.2 ± 1 |
| GDH (deamination) [nmol NADH mg−1 protein min−1] | 3.5 ± 0.3 | 5.3 ± 0.7 | 8.4 ± 2.4* | 4.7 ± 1.5 |
| Ala aminotransferase (nmol NADH mg−1 protein min−1) | 45 ± 6.5 | 41.5 ± 3 | 35.9 ± 5.6 | 43.5 ± 11.6 |
| Asp aminotransferase (nmol NADH mg−1 protein min−1) | 13.4 ± 0.9 | 12.9 ± 1.1 | 13.13 ± 1.6 | 13.9 ± 1.5 |