TABLE 4.
Soil basal respiration, SIR, and QR in soils polluted with different Zn and Cd concentrations at the end of the experimenta
| Soil | Treatment (Zn/Cd) (mg kg−1 [DW]) | Basal respiration (μg C g−1 [DW] soil h−1) | SIR (μg C g−1 [DW] soil h−1) | QR |
|---|---|---|---|---|
| Unplanted | 250/0 | 1.33 ± 0.07AB | 3.38 ± 0.31 | 0.41 ± 0.06 |
| 250/50 | 1.19 ± 0.08BCDE | 6.78 ± 0.17 | 0.18 ± 0.01 | |
| 250/250 | 1.27 ± 0.11ABC | 6.03 ± 0.32 | 0.21 ± 0.01 | |
| 500/0 | 0.88 ± 0.03EFG | 2.96 ± 0.49 | 0.34 ± 0.07 | |
| 500/50 | 0.87 ± 0.01FG | 3.78 ± 0.68 | 0.26 ± 0.05 | |
| 500/250 | 0.95 ± 0.01DEFG | 4.93 ± 0.26 | 0.19 ± 0.01 | |
| 1,000/0 | 0.55 ± 0.07HI | 4.79 ± 0.08 | 0.12 ± 0.01 | |
| 1,000/50 | 0.55 ± 0.04HI | 4.32 ± 0.76 | 0.14 ± 0.02 | |
| 1,000/250 | 0.40 ± 0.02I | 3.75 ± 0.39 | 0.11 ± 0.02 | |
| Planted | 250/0 | 1.51 ± 0.08A | 4.18 ± 0.44 | 0.39 ± 0.07 |
| 250/50 | 1.21 ± 0.03ABCD | 8.46 ± 0.47 | 0.15 ± 0.01 | |
| 250/250 | 0.97 ± 0.01CDEFG | 8.08 ± 0.08 | 0.12 ± 0.00 | |
| 500/0 | 0.95 ± 0.02DEFG | 6.85 ± 1.40 | 0.16 ± 0.03 | |
| 500/50 | 1.23 ± 0.03ABCD | 6.55 ± 1.22 | 0.21 ± 0.03 | |
| 500/250 | 0.81 ± 0.06FGH | 5.94 ± 0.67 | 0.14 ± 0.02 | |
| 1,000/0 | 1.06 ± 0.03BCDEF | 5.92 ± 0.68 | 0.19 ± 0.03 | |
| 1,000/50 | 0.85 ± 0.02FGH | 5.47 ± 0.17 | 0.16 ± 0.01 | |
| 1,000/250 | 0.69 ± 0.05GHI | 7.62 ± 0.92 | 0.10 ± 0.01 |
Values labeled with different letters are significantly different (P < 0.05) according to the Tukey-Kramer test (statistics are shown only when, according to two-way ANOVA, a significant interaction was found between the metal concentration and plant presence). Shown are mean values (n = 4) ± standard errors. ANOVA for columns from left to right (*, significantly different at a P value of < 0.05): plant, <0.0001*, 0.0001*, <0.0001*; metal, <0.0001*, <0.0001*, 0.0340*; plant × metal, <0.0001*, 0.2497, 0.1433; unplanted, Zn, <0.0001*, 0.0033*, 0.0003*; unplanted, Cd, 0.5987, 0.0078*, 0.0050*; unplanted, Zn × Cd, 0.3174, 0.0018*, 0.0404*; planted, Zn, <0.0001*, 0.7233, 0.0562; planted, Cd, <0.0001*, 0.1121, 0.0005*; planted, Zn × Cd, <0.0001*, 0.0341*, 0.0025*.