Table 3.
Comparison of the ratios of concentrations of organic acids in soybean roots and nodules treated with 5 mM of nitrate for 24 h and the control plants.
| Organic Acid | Roots | Nodules |
|---|---|---|
| 2-Isopropylmalic acid | 2.4 * | 1.0 |
| 2-Aminoadipic acid | 2.1 ** | 1.1 |
| N-Acetylglutamic acid | 1.9 ** | 1.1 |
| Citramalic acid | 1.9 ** | 0.9 |
| Fumaric acid | 1.7 *** | 1.0 |
| Argininosuccinic acid | 1.4 ** | 1.3 * |
| Succinic acid | 1.3 * | 0.9 |
| Phosphoenolpyruvic acid | 1.3 * | 0.9 |
| Malic acid | 0.8 * | 0.9 |
Notes: The symbol (*, **, ***) after each number indicates the statistical significance of the metabolite concentration between the nitrate treatment and control at p < 0.05, 0.01, 0.001 levels by Welch’s t-test. Red color stands for Ratio (Nitrate/Control) > 3; Orange stands for 2 ≤ Ratio (Nitrate/Control) ≤ 3; Yellow stands for 1 ≤ Ratio (Nitrate/Control) < 2; Blue stands for Ratio (Nitrate/Control) < 1.