Table 2.
Root length parameters of white lupin, faba bean and maize grown with low (LP) (1 µmol L−1) and high P (HP) (250 µmol L−1) under two N forms [ca(NO3)2 and NH4NO3] for 7, 12 and 16 days.
| Parameters | Ca(NO3)2 as N source |
NH4NO3 as N source |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| White lupin |
Faba bean |
Maize |
White lupin |
Faba bean |
Maize |
|||||||
| LP | HP | LP | HP | LP | HP | LP | HP | LP | HP | LP | HP | |
| 7 days | ||||||||||||
| TRL (m) | 1.6 b | 2.0 a | 4.6 b | 6.1 a | 14.5 a | 12.4 b | 1.8 a | 1.7 a | 4.7 a | 4.8 a | 20.9 a | 14.9 b |
| ARL (cm) | 28.3 b | 31.5 a | 32.3 a | 36.0 a | 251.6 a | 219.5 b | 23.8 b | 26.9 a | 26.1 a | 29.7 a | 221.4 a | 189.9 b |
| LRD (no. cm−1) | 2.6 a | 2.4 a | 1.4 b | 1.7 a | 4.0 a | 3.4 b | 2.7 a | 2.1 b | 3.5 a | 2.5 b | 3.9 a | 3.4 b |
| SRL (m g−1) | 41.2 a | 41.4 a | 27.0 a | 33.5 a | 111.3 a | 113.6 a | 43.7 a | 38.0 b | 28.5 a | 28.0 a | 159.0 a | 147.9 a |
| 12 days | ||||||||||||
| TRL (m plant−1) | 3.9 a | 4.9 a | 11.0 a | 8.8 b | 33.6 a | 24.5 b | 3.9 a | 4.3 a | 9.0 a | 9.8 a | 47.4 a | 26.9 b |
| ARL (cm) | 36.0 a | 35.7 a | 38.7 a | 42.4 a | 497.4 a | 336.8 b | 34.9 a | 38.9 a | 39.0 a | 41.2 a | 420.5 a | 301.7 b |
| LRD (no. cm−1) | 3.9 a | 2.9 b | 2.0 a | 1.6 b | 3.7 a | 3.5 b | 3.2 a | 3.5 a | 2.8 a | 2.9 a | 4.8 a | 4.1 b |
| SRL (m g−1) | 86.0 a | 73.9 b | 36.7 a | 43.0 a | 176.2 a | 150.0 b | 82.4 a | 80.7 a | 42.8 a | 36.8 b | 226.0 a | 216.1 a |
| 16 days | ||||||||||||
| TRL (m) | 6.2 a | 6.3 a | 23.5 a | 13.1 b | 43.2 a | 36.2 b | 5.8 a | 6.9 a | 10.7 b | 18.2 a | 52.7 a | 50.5 a |
| ARL (cm) | 52.9 a | 48.6 a | 51.8 a | 1.6 b | 506.8 a | 454.3 b | 36.6 b | 46.8 a | 46.8 a | 46.2 a | 508.3 a | 450.1 a |
| LRD (no. cm−1) | 3.7 a | 3.5 a | 1.8 a | 1.6 b | 4.0 a | 3.5 b | 3.6 a | 3.5 a | 2.1 b | 2.8 a | 4.5 a | 4.4 a |
| SRL (m g−1) | 74.6 a | 68.1 a | 73.6 a | 63.8 b | 196.9 a | 189.1 b | 79.7 a | 82.5 a | 56.2 b | 72.7 a | 201.1 b | 269.7 a |
Values of each pair in rows of individual plant species followed by different letters represent significant differences between the P treatments (P < 0.05). Means ± SE, n = 4. Abbreviations: TRL: total root length (m plant−1); ARL: axial root length (cm); LRD: lateral root density (number of lateral roots per unit axial root, no./cm); SRL, specific root length (m g−1).